Wireless local area network access method, base station controller, and user equipment

ABSTRACT

The present application provides a method for accessing a wireless local area network, a base station controller, and a user equipment. The method includes: determining, by a base station controller of a user equipment, a first access point set, and sending information about the first access point set to the user equipment; and determining, by the user equipment according to the first access point set, an access point for accessing a wireless local area network. In embodiments of the present application, when a user equipment needs to access a wireless local area network through an access point to access the Internet, a base station controller may notify the user equipment of an available access point. In this way, the user equipment can access the wireless local area network directly through the available access point and does not need to request a password from an operator and enter the password during access.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/670,263, filed Mar. 26, 2015, which is a continuation ofInternational Application No. PCT/CN2012/082358, filed on Sep. 28, 2012,All of the afore-mentioned patent applications are hereby incorporatedby reference in their entireties.

TECHNICAL FIELD

Embodiments of the present application relate to the field ofcommunications technologies, and in particular, to a method foraccessing a wireless local area network, a base station controller, anda user equipment

BACKGROUND

With the popularity of a wireless local area network (WEAN), an operatormay construct the WLAN in some places (for example, a shopping mall andan office building) while operating a mobile network. When a userequipment (UE) is within the coverage of the WLAN, it is capable ofaccessing the Internet through a WLAN access point (Access Point, AP) toperform operations such as web browsing and download. When the userequipment needs to access the Internet through the WLAN, the userequipment needs to request a password of the WLAN AP from the operatorby using a short message or in another manner, and needs to enter thepassword when accessing the AP.

SUMMARY

The present application provides a method for accessing a wireless localarea network, a base station controller, and a user equipment, so thatwhen needing to access the Internet through an AP, the user equipmentdoes not need to request a password from an operator and enter thepassword during access.

In a first aspect, the present application provides a method foraccessing a wireless local area network WLAN, the method is performed bya base station controller of a serving base station of a user equipmentand includes: determining a first access point AP set in the case ofreceiving an access capability indication or access request sent by theuser equipment, where the first AP set includes at least one AP; andsending information about the first AP set to the user equipmentaccording to the first AP set, so that the user equipment determines,according to the information about the first AP set, an access AP foraccessing a WLAN.

With reference to the first aspect, in a first possible implementationmanner, the information about the first AP set includes at least one ofthe following: a channel number of at least one AP in the first AP set,identification information of at least one AP in the first AP set,information about a beacon channel of at least one AP in the first APset, and a security parameter of at least one AP in the first AP set,where the information about the beacon channel of the at least one AP inthe first AP set is a sending time point and period of the beaconchannel of the at least one AP in the first AP set, and the securityparameter of the at least one AP in the first AP set includes a key usedfor access and/or an authentication type.

With reference to the first aspect or the first possible implementationmanner of the first aspect, in a second possible implementation manner,after the sending information about the first AP set to the userequipment, the method further includes: receiving information about asecond AP set sent by the user equipment, where the second AP setincludes at least one AP, and the second AP set is determined by theuser equipment from the at least one AP in the first AP set;

determining a third AP set from the at least one AP in the second APset, where the third AP set includes at least one AP; and

sending information about the third AP set to the user equipmentaccording to the third AP set, so that the user equipment determines,from the at least one AP in the third AP set, the access AP foraccessing the WLAN.

With reference to the second possible implementation manner of the firstaspect, in a third possible implementation manner, the information aboutthe second AP set includes: first information and second information;

the first information includes signal quality of at least one AP in thesecond AP set and/or signal strength of at least one AP in the second APset; and

the second information includes at least one of the following: a channelnumber of at least one AP in the second AP set, identificationinformation of at least one AP in the second AP set, and informationabout a beacon channel of at least one AP in the second AP set, wherethe information about the beacon channel of the at least one AP in thesecond AP set is a sending time point and period of the beacon channelof the at least one AP in the second AP set.

With reference to the second possible implementation manner or the thirdpossible implementation manner of the first aspect, in a fourth possibleimplementation manner, the information about the third AP set includesat least one of the following:

a channel number of at least one AP in the third AP set, identificationinformation of at least one AP in the third AP set, information about abeacon channel of at least one AP in the third. AP set, and a securityparameter of at least one AP in the third. AP set, where the informationabout the beacon channel of the at least one AP in the third AP set is asending time point and period of the beacon channel of the at least oneAP in the third AP set, and the security parameter of the at least oneAP in the third AP set includes a key used for access and/or anauthentication type.

With reference to the first aspect or any one of the preceding possibleimplementation manners of the first aspect, in a fifth possibleimplementation manner, after the sending information about the first APset to the user equipment, the method further includes:

receiving identification information of the access AP sent by the userequipment or the access AP.

With reference to the fifth possible implementation manner of the firstaspect, in a sixth possible implementation manner, after the receivingidentification information of the access AP sent by the user equipment,the method further includes:

determining a fourth AP set according to location information of theaccess AP, where the fourth AP set includes at least one AP; and

notifying the user equipment of the fourth AP set.

With reference to the first aspect or any one of the preceding possibleimplementation manners of the first aspect, in a seventh possibleimplementation manner, the method further includes:

sending a first threshold to the user equipment, where the firstthreshold is used for the user equipment accessing the base stationcontroller; or

sending a first threshold and a second threshold to the user equipment,where the second threshold is used for the user equipment determining aswitching target or a candidate target set, the candidate target setincludes one or more AP, the first threshold is used for the userequipment accessing the switching target, and the switching target is anAP or the base station controller.

With reference to the seventh possible implementation manner of thefirst aspect, in an eighth possible implementation manner, the switchingtarget is an AP, and the method further includes:

receiving identification information of the switching target sent by theuser equipment or the switching target.

With reference to the seventh possible implementation manner or theeighth possible implementation manner of the first aspect, in a ninthpossible implementation manner, the method further includes:

in a case where the switching target is an AP, receiving an associationmessage and/or an authentication message sent by the user equipment tothe switching target, and forwarding the association message and/or theauthentication message to the switching target; or

in a case where the candidate target set is determined, receiving anassociation message and/or an authentication message sent by the userequipment to t least one AP in the candidate target set, and forforwarding the association message and/or the authentication message tothe at least one AP in the candidate target set.

With reference to any one of the seventh possible implementation mannerto the ninth possible implementation manner of the first aspect, in atenth possible implementation manner, the method further includes:

receiving the candidate target set notified by the user equipment;

determining a switching target from the one or more AP in the candidatetarget set; and

notifying the user equipment of the switching target.

With reference to the seventh possible implementation manner of thefirst aspect, in an eleventh possible implementation manner, the methodfurther includes:

receiving a connection establishment request or a data transmissionstate message sent by the user equipment, where the connectionestablishment request is used to reestablish a connection between theuser equipment and the base station controller, and the datatransmission state message is used to restore a state of datatransmission between the user equipment and the base station controller.

With reference to the eleventh possible implementation manner of thefirst aspect, in a twelfth possible implementation manner, the datatransmission state message includes a measurement report or a cellupdate request.

With reference to the eleventh possible implementation manner or thetwelfth possible implementation manner of the first aspect, in athirteenth possible implementation manner, the connection establishmentrequest or the data transmission state message further includesindication information used to indicate that the WLAN is unavailable.

With reference to the first possible implementation manner, the thirdpossible implementation manner, or the fourth possible implementationmanner of the first aspect, in a fourteenth possible implementationmanner, the sending time point of the beacon channel is relative timeinformation of the beacon channel relative to a reference time of amobile network cell.

With reference to the fourteenth possible implementation manner of thefirst aspect, in a fifteenth possible implementation manner, thereference time of the mobile network cell is a system frame number orconnection frame number.

With reference to the first aspect or any one of the preceding possibleimplementation manners of the first aspect, in a sixteenth possibleimplementation manner, the access capability indication and the accessrequest are carried in a radio resource control RRC connectionestablishment request message or an RRC connection establishmentcomplete message; or

the information about the first AP set is carried in an RRC connectionestablishment message, an RRC connection release message or ameasurement control message.

With reference to the sixteenth possible implementation manner of thefirst aspect, in a seventeenth possible implementation manner, in a casewhere the information about the first AP set is carried in the RRCconnection release message, an RRC connection to the user equipment isreleased.

In a second aspect, the present application provides a method foraccessing a wireless local area network WLAN, the method is performed bya user equipment and includes:

sending an access capability indication or access request of the userequipment to a base station controller of a serving base station of theuser equipment, so that the base station controller determines a firstaccess point AP set in the case of receiving the access capabilityindication or the access request, where the first AP set includes atleast one AP;

receiving information about the first AP set sent by the base stationcontroller; and determining, according to the information about thefirst AP set, an access AP for accessing a WLAN.

With reference to the second aspect, in a first possible implementationmanner, the information about the first AP set includes at least one ofthe following:

a channel number of at least one AP in the first AP set, identificationinformation of at least one AP in the first AP set, information about abeacon channel of at least one AP in the first AP set, and a securityparameter of at least one AP in the first AP set, where the informationabout the beacon channel of the at least one AP in the first AP set is asending time point and period of the beacon channel of the at least oneAP in the first AP set, and the security parameter of the at least oneAP in the first AP set includes a key used for access and/or anauthentication type.

With reference to the second aspect or the first possible implementationmanner of the second aspect, in a second possible implementation manner,the determining, according to the information about the first AP set, anaccess AP for accessing a WLAN includes:

determining the access AP from the at least one AP in the first AP set.

With reference to the second aspect or the first possible implementationmanner of the second aspect, in a third possible implementation manner,the determining, according to the information about the first AP set, anaccess AP for accessing a WLAN includes:

determining a second AP set from the at least one AP in the first APset, where the second AP set includes at least one AP;

sending information about the second AP set to the base stationcontroller according to the second AP set;

receiving information about a third AP set sent by the base stationcontroller, where the third AP set is determined by the base stationcontroller from the at least one AP in the second AP set, and the thirdAP set includes at least one AP; and

determining the access AP from the at least one AP in the third AP set.

With reference to the third possible implementation manner of the secondaspect, in a fourth possible implementation manner, the informationabout the second AP set includes: first information and secondinformation;

the first information includes signal quality of at least one AP in thesecond AP set and/or signal strength of at least one AP in the second APset; and

the second information includes at least one of the following: a channelnumber of at least one AP in the second AP set, identificationinformation of at least one AP in the second AP set, and informationabout a beacon channel of at least one AP in the second AP set, wherethe information about the beacon channel of the at least one AP in thesecond AP set is a sending time point and period of the beacon channelof the at least one AP in the second AP set.

With reference to the third possible implementation manner or the fourthpossible implementation manner of the second aspect, in a fifth possibleimplementation manner, the information about the third AP set includesat feat one of the following:

a channel number of at least one AP in the third AP set, identificationinformation of at least one AP in the third AP set, information about abeacon channel of at least one AP in the third AP set, and a securityparameter of at least one AP in the third AP set, where the informationabout the beacon channel of the at least one AP in the third AP set is asending time point and period of the beacon channel of the at least oneAP in the third AP set, and the security parameter of the at least oneAP in the third AP set includes a key used for access and/or anauthentication type.

With reference to the second aspect or any one of the preceding possibleimplementation manners of the second aspect, in a sixth possibleimplementation manner, after the determining the access AP, the methodfurther includes:

sending identification information of the access AP to the base stationcontroller.

With reference to the sixth possible implementation manner of the secondaspect, in a seventh possible implementation manner, after the sendingidentification information of the access AP to the base stationcontroller, the method further includes:

receiving a fourth AP set notified by the base station controller, wherethe fourth AP set includes at least one AP.

With reference to the second aspect or any one of the preceding possibleimplementation manners of the second aspect, in an eighth possibleimplementation manner, the method further includes:

receiving a first threshold sent by the base station controller, andaccessing the base station controller according to the first threshold.

With reference to the second aspect or any one of the first possibleimplementation manner to the seventh possible implementation manner ofthe second aspect, in a ninth possible implementation manner, the methodfurther includes:

receiving a first threshold and a second threshold that are sent by thebase station controller, determining that a switching target is an AP orthe base station controller according to the second threshold, andaccessing the switching target according to the first threshold; or

receiving a first threshold and a second threshold that are sent by thebase station controller, determining a candidate target set according tothe second threshold, where the candidate target set includes at leastone AP, notifying the base station controller of the candidate targetset, and receiving a switching target, where the switching target isdetermined by the base station controller from the at least one AP inthe candidate target set, and accessing the switching target accordingto the first threshold.

With reference to the ninth possible implementation manner of the secondaspect, in a tenth possible implementation manner, the method furtherincludes:

in the case of determining that the switching target is an AP, sendingan association message and/or an authentication message to the AP whichis the switching target through the base station controller; or

in the case of determining the candidate target set, sending anassociation message and/or an authentication message to at least one APin the candidate target set through the base station controller.

With reference to the ninth possible implementation manner of the secondaspect, in an eleventh possible implementation manner, the switchingtarget is an AP, and the method further includes:

sending identification information of the switching target to the basestation controller.

With reference to the eighth possible implementation manner of thesecond aspect or the ninth possible implementation manner of the secondaspect, in a twelfth possible implementation manner, the accessing thebase station controller includes:

sending a connection establishment request or a data transmission statemessage to the base station controller, where the connectionestablishment request is used to reestablish a connection with the basestation controller, and the data transmission state message is used torestore a state of data transmission with the base station controller.

With reference to the twelfth possible implementation manner of thesecond aspect, in a thirteenth possible implementation manner, the datatransmission state message includes a measurement report or a cellupdate request.

With reference to the twelfth possible implementation manner or thethirteenth possible implementation manner of the second aspect, in afourteenth possible implementation manner, the connection establishmentrequest or the data transmission state message further includesindication information used to indicate that the WLAN is unavailable.

With reference to the first possible implementation manner of the secondaspect, the fourth possible implementation manner of the second aspect,or the fifth possible implementation manner of the second aspect, in afifteenth possible implementation manner, the sending time point of thebeacon channel is relative time information of the beacon channelrelative to a reference time of a mobile network cell.

With reference to the fifteenth possible implementation manner of thesecond aspect, in a sixteenth possible implementation manner, thereference time of the mobile network cell is a system frame number orconnection frame number.

With reference to the second aspect or any one of the preceding possibleimplementation manners of the second aspect, in a seventeenth possibleimplementation manner, the access capability indication and the accessrequest are carried in a radio resource control RRC connectionestablishment request message or an RRC connection establishmentcomplete message.

With reference to the second aspect or any one of the preceding possibleimplementation manners of the second aspect, in an eighteenth possibleimplementation manner, the information about the first AP set is carriedin an RRC connection establishment message, an RRC connection releasemessage or a measurement control message.

With reference to the eighteenth possible implementation manner of thesecond aspect, in a nineteenth possible implementation manner, in a casewhere the information about the first AP set is carried in the RRCconnection release message, the method further includes: releasing anRRC connection between the user equipment and the base stationcontroller.

In a third aspect, the present application provides a base stationcontroller, the base station controller is a base station controller ofa serving base station of a user equipment and includes:

a receiving unit, configured to receive an access capability indicationor access request sent by the user equipment;

a control unit, configured to determine a first access point AP set in acase where the receiving unit receives the access capability indicationor access request sent by the user equipment, where the first AP setincludes at least one AP; and

a sending unit, configured to send information about the first AP set tothe user equipment according to the first AP set determined by thecontrol unit, so that the user equipment determines, according to theinformation about the first AP set, an access AP for accessing a WLAN.

With reference to the third aspect, in a first possible implementationmanner:

the receiving unit is further configured to receive information about asecond AP set sent by the user equipment, where the second AP setincludes at least one AP;

the control unit is further configured to determine a third AP set fromthe at least one AP in the second AP set, where the third AP setincludes at least one AP; and

the sending unit is further configured to send information about thethird AP set to the user equipment, so that the user equipmentdetermines, from the at least one AP in the third AP set, the access APfor accessing the WLAN.

With reference to the third aspect or the first possible implementationmanner of the third aspect, in a second possible implementation manner:

the receiving unit is further configured to receive identificationinformation of the access AP sent by the user equipment or the accessAP.

With reference to the second possible implementation manner of the thirdaspect, in a third possible implementation manner:

the control unit is further configured to determine a fourth AP setaccording to location information of the access AP, where the fourth APset includes at least one AP; and the sending unit is further configuredto notify the user equipment of the fourth AP set.

With reference to the third aspect or any one of the preceding possibleimplementation manners of the third aspect, in a fifth possibleimplementation manner:

the sending unit is further configured to send a first threshold to theuser equipment, where the first threshold is used for the user equipmentaccessing the base station controller; or

the sending unit is further configured to send a first threshold and asecond threshold to the user equipment, where the second threshold isused for the user equipment determining a switching target or acandidate target set, the candidate target set includes one or more AP,the first threshold is used for the user equipment accessing theswitching target, and the switching target is an AP or the base stationcontroller.

With reference to the fifth possible implementation manner of the thirdaspect, in a sixth possible implementation manner, the switching targetis an AP, and

the receiving unit is further configured to receive identificationinformation of the switching target sent by the user equipment or theswitching target.

With reference to the fifth possible implementation manner of the thirdaspect or the sixth possible implementation manner of the third aspect,in a seventh possible implementation manner:

the receiving unit is further configured to receive an associationmessage and/or an authentication message sent by the user equipment toat least one AP in the candidate target set or the switching target; and

the sending unit is further configured to forward the associationmessage and/or the authentication message to the at least one AP in thecandidate target set or the switching target.

With reference to any one of the fifth possible implementation manner tothe seventh possible implementation manner of the third aspect, in aneighth possible implementation manner:

the receiving unit is further configured to receive the candidate targetset notified by the user equipment;

the control unit is further configured to determine a switching targetfrom the one or more AP in the candidate target set; and

the sending unit is further configured to notify he user equipment ofthe switching target.

With reference to the fifth possible implementation manner of the thirdaspect, in ninth possible implementation manner:

the receiving unit is further configured to receive a connectionestablishment request or a data transmission state message sent by theuser equipment; and

the control unit is further configured to control reestablishment of aconnection to the user equipment in a case where the receiving unitreceives the connection establishment request, or control restoration ofa connection to the user equipment in a case where the receiving unitreceives the data transmission state message.

In a fourth aspect, the present application provides a user equipment,including:

a sending unit, configured to send an access capability indication ofthe user equipment or access request to a base station controllerconnected to a serving base station of the user equipment;

a receiving unit, configured to receive information about a first accesspoint AP set sent by the base station controller, where the first AP setincludes at least one AP; and

a control unit, configured to determine, according to the informationabout the first AP set received by the receiving unit, an access AP foraccessing a wireless local area network WLAN.

With reference to the fourth aspect, in a first possible implementationmanner:

the control unit is specifically configured to determine the access APfrom the at least one AP in the first AP set.

With reference to the fourth aspect, in a second possible implementationmanner:

the control unit is further configured to determine a second AP set fromthe at least one AP in the first AP set, where the second AP setincludes at least one AP;

the sending unit is further configured to send information about thesecond AP set to the base station controller;

the receiving unit is further configured to receive information about athird AP set sent by the base station controller, where the third AP setis determined by the base station controller from the at least one AP inthe second AP set, and the third AP set includes at least one AP; and

the control unit is further configured to determine the access AP fromthe at least one AP in the third AP set.

With reference to the fourth aspect or any one of the preceding possibleimplementation manners of the fourth aspect, in a third possibleimplementation manner:

the sending unit is further configured to send identificationinformation of the access AP to the base station controller.

With reference to the third possible implementation manner of the fourthaspect, in a fourth possible implementation manner:

the receiving unit is further configured to receive a fourth AP setnotified by the base station controller, where the fourth AP setincludes at least one AP.

With reference to the fourth aspect or any one of the preceding possibleimplementation manners of the fourth aspect, in a fifth possibleimplementation manner:

the receiving unit is further configured to receive a first thresholdsent by the base station controller; and

the control unit is further configured to access the base stationcontroller according to the first threshold.

With reference to the fourth aspect or any one of the first possibleimplementation manner to the fourth possible implementation manner ofthe fourth aspect, in a sixth possible implementation manner:

the receiving unit is further configured to receive a first thresholdand a second threshold that are sent by the base station controller; and

the control unit is further configured to determine that a switchingtarget is an AP or the base station controller according to the secondthreshold, and access the AP or the base station controller according tothe first threshold.

With reference to the sixth possible implementation manner of the fourthaspect, in a seventh possible implementation manner:

the sending unit is further configured to: in a case where the switchingtarget is an AP, send an association message and/or an authenticationmessage to the AP through the base station controller.

With reference to the sixth possible implementation manner of the fourthaspect or the seventh possible implementation manner of the fourthaspect, in an eighth possible implementation manner:

the sending unit is further configured to: in a case where the switchingtarget is an AP, send identification information of the AP to the basestation controller.

With reference to the fifth possible implementation manner of the fourthaspect or the sixth possible implementation manner of the fourth aspect,in a ninth possible implementation manner:

the sending unit is further configured to send a connectionestablishment request or a data transmission state message to the basestation controller, so that the user equipment accesses the base stationcontroller.

With reference to he fourth aspect or any one of the first possibleimplementation manner to the fourth possible implementation manner ofthe fourth aspect, in a tenth possible implementation manner:

the receiving unit is further configured to receive a first thresholdand a second threshold that are sent by the base station controller;

the control unit is further configured to determine a candidate targetset according to the second threshold, where the candidate target setincludes at least one AP;

the sending unit is further configured to notify the base stationcontroller of the candidate target set;

the receiving unit is further configured to receive information about aswitching target, where the switching target is determined by the basestation controller from the at least one AP in the candidate target set;and

the control unit is further configured to control access to theswitching target.

In embodiments of the present application, when a user equipment needsto access a WLAN through an AP to access the Internet, a base stationcontroller may notify the user equipment of an available AP. In thisway, the user equipment can access the WLAN directly through theavailable AP and does not need to request a password from an operatorand enter the password during access.

BRIEF DESCRIPTION OF DRAWINGS

To illustrate the technical solutions in the embodiments of the presentapplication more clearly, the following briefly introduces theaccompanying drawings required for describing the embodiments of thepresent application. Apparently, the accompanying drawings in thefollowing description show merely some embodiments of the presentapplication, and a person of ordinary skill in the art may still deriveother drawings from these accompanying drawings without creativeefforts.

FIG. 1 is a schematic flowchart of a method for accessing a wirelesslocal area network according to an embodiment of the presentapplication;

FIG. 2 is a schematic flowchart of a method for accessing a wirelesslocal area network according to an embodiment of the presentapplication;

FIG. 3 is a schematic flowchart of a method for accessing a wirelesslocal area network according to an embodiment of the presentapplication;

FIG. 4 is a schematic block diagram of a base station controlleraccording to an embodiment of the present application;

FIG. 5 is a schematic block diagram of another base station controlleraccording to an embodiment of the present application;

FIG. 6 is a schematic block diagram of a user equipment according to anembodiment of the present application; and

FIG. 7 is a schematic block diagram of another user equipment accordingto an embodiment of the present application.

DESCRIPTION OF EMBODIMENTS

The following clearly describes the technical solutions in theembodiments of the present application with reference to theaccompanying drawings in the embodiments of the present application.Apparently, the described embodiments are merely a part rather than allof the embodiments of the present application. All other embodimentsobtained by a person of ordinary skill in the art based on theembodiments of the present application without creative efforts shallfall within the protection scope of the present application.

It should be understood that the technical solutions in the embodimentsof the present application may be applied to various communicationssystems, for example, a global system of mobile communications (“GSM”for short) system, a code division multiple access (“CDMA” for short)system, a wideband code division multiple access (“WCDMA” for short)system, a general packet radio service (“GPRS” for short), a long termevolution (“LTE” for short) system,an LTE frequency division duplex(“FDD” for short) system, LTE time division duplex (“TDD” for short),and a universal mobile telecommunication system (“UNITS” for short) andthe like.

A UE, may also be called a mobile terminal (MT), a mobile userequipment, or the like, and is capable of communicating with at leastone core networks through a radio access network (for example, RadioAccess Network, RAN). The user equipment may be a mobile terminal, forexample a mobile phone (or called a “cellular” phone), or a computerhaving a mobile terminal, for example, a portable, pocket, handheld,computer-embedded, or vehicle-mounted mobile apparatus.

A base station may be a base station (Base Transceiver Station, BTS) inthe GSM or the CDMA, a base station (Node B) in the WCDMA, or an eNB ore-NodeB in the LTE, which is not limited in the present application.

A base station controller may be a BSC (base station controller), an RNC(radio network controller), or an eNode B (evolved Node B), which is notlimited in the present application. The base station controller isconnected with an AP for information exchange.

An AP described in this document refers to a WLAN AP. The user equipmentmay be connected with the Internet through the AP. The AP may be anindependent AP controlled and managed by an AC (access controller), oran AP including an AC function, and may also form a special base stationwith a base station, which is not limited in the present application.

A WLAN may be wireless fidelity (WiFi) or worldwide interoperability formicrowave access (WiMAX), which is not limited in the presentapplication.

The mobile network described in this document may be variouscommunications systems, for example, a Global System of MobileCommunication (“GSM” for short) system, a Code Division Multiple Access(“CDMA” for short) system, a Wideband Code Division Multiple Access(“WCDMA” for short) system, a general packet radio service (“GPRS” forshort), a Long Term Evolution (“LTE” for short) system, an LTE frequencydivision duplex (“FDD” for short) system, LTE time division duplex(“TDD” for short), and a Universal Mobile Telecommunication System(“UNITS” for short).

FIG. 1 is a schematic flowchart of a method for accessing a WLANaccording to an embodiment of the present application. The method inFIG. 1 is performed by a base station controller of a serving basestation of a user equipment.

101. Determine a first AP set in the case of receiving an accesscapability indication or access request sent by the user equipment,where the first AP set includes at least one AP, and the accesscapability indication sent by the user equipment is used to indicatethat the user equipment is capable of accessing a WLAN through an AP.

102. Send information about the first AP set to the user equipmentaccording to the first AP set, so that the user equipment determines,according to the information about the first AP set, an access AP foraccessing the WLAN.

Optionally, the information about the first AP set includes at least oneof the following: a channel number of at least one AP in the first APset, identification information of at least one AP in the first AP set,information about a beacon channel of at least one AP in the first APset, a security parameter of at least one AP in the first AP set,transmit signal strength of at least one AP in the first AP set, andtransmit signal quality of at least one in the first AP set, where theinformation about the beacon channel of the at least one AP in the firstAP set is a sending time point and period of the beacon channel of theat least one AP in the first AP set, and the security parameter of theat least one AP in the first AP set includes a key used for accessand/or an authentication type.

The sending time point of the beacon channel refers to relative timeinformation of the beacon channel relative to a reference time of amobile network cell. The reference time of the mobile network cell maybe a system frame number and may also be connection frame number. Theuser equipment calculates, according to the relative time of the beaconchannel and the reference time of the mobile network cell, a time whenthe beacon channel possibly appears, so as to accelerate AP search. Forexample, the reference time of the mobile network cell of the beaconchannel is SFN (System Frame Number, system frame number) 1, and aperiod is 100 milliseconds; because a time length of each SFN is 10milliseconds, reference time points at which the beacon channel possiblyappears are SFN 1, SFN 11, and SFN 21; therefore, the user equipmentdoes not need to wait all the time for the beacon channel to appear andmay search for the beacon channel only at the reference time points toimprove search efficiency, thereby accelerating the search.

Optionally, identification information of an AP or access AP in the setis a unique identifier corresponding to the AP, for example, a basicservice set identifier (BSSM), a service set identifier (SSID), anextended service set identifier (ESSID), or a media access control (MAC)address.

According to the preceding method, when a user equipment needs to accessa WLAN through an AP to access the Internet, a base station controllermay notify the user equipment of an available AP. In this way, the userequipment can access the WLAN directly through the available AP and doesnot need to request a password from an operator and enter the passwordduring access.

FIG. 2 is a schematic flowchart of a method for accessing a WLANaccording to an embodiment of the present application. The method inFIG. 2 is performed by a user equipment.

201. Send an access capability indication or access request of the userequipment to a base station controller of a serving base station of theuser equipment, so that the base station controller determines a firstAP set in the case of receiving the access capability indication or theaccess request, where the first AP set includes at least one AP, and theaccess capability indication sent by user equipment is used to indicatethat the user equipment is capable of accessing a WLAN through an AP.

202. Receive information about the first AP set sent by the base stationcontroller.

203. Determine, according to the information about the first AP set, anaccess AP for accessing the WLAN.

Optionally, the information about the first AP set includes at least oneof the following: a channel number of at least one AP in the first APset, identification information of at least one AP in the first AP set,information about a beacon channel of at least one AP in the first APset, a security parameter of at least one AP in the first AP set,transmit signal strength of at least one AP in the first AP set, andtransmit signal quality of at least one AP in the first AP set, wherethe information about the beacon channel of the at least one AP in thefirst AP set is a sending time point and period of the beacon channel ofthe at least one AP in the first AP set, and the security parameter ofthe at least one AP in the first AP set includes a key used for accessand/or an authentication type.

Optionally, identification information of an AP or access AP in the setis a unique identifier corresponding to the AP, for example, a BSSID, anSSID, an ESSID, or a MAC address.

According to the preceding method, when a user equipment needs to accessa WLAN through an AP to access the Internet, a base station controllermay notify the user equipment of an available AP. In this way, the userequipment can access the WLAN directly through the available AP and doesnot need to request a password from an operator and enter the passwordduring access.

FIG. 3 is a schematic flowchart of a method for accessing a WLANaccording to an embodiment of the present application.

301. A user equipment sends an access capability indication or an accessrequest to a base station controller of a serving base station of theuser equipment, where the access capability indication is used toindicate that the user equipment is capable of accessing a WLAN throughan AP.

Optionally, the access capability indication and the access request maybe carried in a radio resource control (RRC) connection establishmentrequest message or an RRC connection establishment complete message. TheRRC connection establishment request message is the first message sentby the user equipment to a mobile network, and the RRC connectionestablishment complete message is the first dedicated message sent bythe user equipment to the mobile network. Using the RRC connectionestablishment request message or the RRC connection establishmentcomplete message to bear the access capability indication and the accessrequest helps the base station controller quickly perform WLAN accesscontrol according to the access request.

302. The base station controller determines a first AP set in the caseof receiving the access capability indication or the access request,where the first AP set includes at least one AP.

303. The base station controller sends information about the first APset to the user equipment according to the first AP set.

Optionally, the information about the first AP set includes at least oneof the following: a channel number of at least one AP in the first APset, identification information of at least one AP in the first AP set,information about a beacon channel of at least one AP in the first APset, a security parameter of at least one AP in the first AP set,transmit signal quality of at least one AP in the first AP set, andtransmit signal strength of at least one AP in the first AP set, wherethe information about the beacon channel of the at least one AP in thefirst AP set is a sending time point and period of the beacon channel ofthe at least one AP in the first AP set, and the security parameter ofthe at least one AP in the first AP set includes a key used for accessand/or an authentication type.

Optionally, the information about the first AP set may be carried in anRRC connection establishment message, an RRC connection release messageor a measurement control message. In a case where the information aboutthe first AP set is carried in the RRC connection release message, thebase station controller releases an RRC connection to the userequipment.

304. In the case of receiving the information about the first AP set,the user equipment determines, from the at least one AP in the first APset, an access AP for accessing the WLAN.

Optionally, in a case where the first AP set includes only one AP, theuser equipment determines that the access AP is the AP. The userequipment may further determine at least one of the following accordingto the information about the first AP set: signal strength of at leastone AP in the first AP set, signal quality of at least one AP in thefirst AP set, and a path loss of at least one AP in the first AP set.The user equipment may select an AP with the highest signal quality orsignal strength in the first AP set as the access AP, and may alsoselect an AP with the lowest path loss in the first AP set as the accessAP.

305. The user equipment may determine a second AP set from the at leastone AP in the first AP set in the case of receiving the informationabout the first AP set, where the second AP set includes at least oneAP.

Optionally, in the case of receiving the information about the first APset, the user equipment may determine at least one of the followingaccording to the information about the first AP set: the signal strengthof the at least one AP in the first AP set, the signal quality of the atleast one AP in the first AP set, and the path loss of the at least oneAP in the first AP set. The user equipment may determine an AP in thesecond AP set from the at least one AP in the first AP set according toa preset condition. For example, the user equipment may determine an APwhose signal quality or signal strength is higher than a specifiedthreshold as an AP in the second AP set, and the user equipment may alsodetermine, according to a specified proportion, an AP whose signalquality or signal strength ranks high as an AP in the second AP set. Itshould be noted that the preceding method is only an example, a methodfor determining an AP in the second. AP set is not limited to thepreceding method.

306. The user equipment sends information about the second AP set to thebase station controller according to the second AP set.

Optionally,the information about the second AP set includes: firstinformation and second information, where the first information includesat least one of the following: signal quality of the at least one AP inthe second AP set, signal strength of the at least one AP in the secondAP set, and a path loss of the at least one AP in the second AP set, andthe second information includes at least one of the following: a channelnumber of at least one AP in the second AP set, identificationinformation of at least one AP in the second AP set, and informationabout a beacon channel of at least one AP in the second AP set, wherethe information about the beacon channel of the at least one AP in thesecond AP set is a sending time point and period of the beacon channelof the at least one AP in the second AP set.

307. The base station controller determines a third AP set from the atleast one AP in the second AP set, where the third AP set includes atleast one AP.

Optionally, the base station controller may determine the third AP setfrom the at least one AP in the second AP set according to a presetcondition. For example, the base station controller may determine an APwhose signal quality or signal strength is higher than a specifiedthreshold as an AP in the third AP set, the base station controller mayalso determine, according to a specified proportion, an AP whose signalquality or signal strength ranks high as an AP in the third AP set, andthe base station controller r ray also determine an AP in the third APset according to other information (for example, load and a congestiondegree of a backhaul) about the at least one AP in the second AP set. Itshould be noted that the preceding method is only an example, a methodfor determining an AP in the third AP set is not limited to thepreceding method.

308. The base station controller sends information about the third APset to the user equipment according to the third AP set.

Optionally, the information about the third. AP set includes at leastone of the following: a channel number of at least one AP in the thirdAP set, identification information of at least one AP in the third APset, information about a beacon channel of at least one AP in the thirdAP set, a security parameter of at least one AP in the third AP set,transmit signal strength of at least one AP in the third AP set, andtransmit signal quality of at least one AP in the third AP set, wherethe information about the beacon channel of the at least one AP in thethird AP set is a sending time point and period of the beacon channel ofthe at least one AP in the third AP set, and the security parameter ofthe at least one AP in the third AP set includes a key used for accessand/or an authentication type.

309. The user equipment determines, from the third AP set, an access APfor accessing the WLAN.

Optionally, in a case where only one AP exists in the third AP set, theaccess AP is the AP. In a case where snore than one AP exists in thethird AP set, the user equipment may select an AP with the highestsignal quality or signal strength in the third AP set as the access AP,and may also select an AP with the lowest path loss in the third AP setas the access AP. The signal strength, signal quality, or path loss ofan AP in the third AP set may be determined by the user equipmentaccording to the information about the third AP set.

1t should be noted that the user equipment may determine the access APby performing step 304, or the user equipment may also determine theaccess AP by performing step 305 to step 309. If the user equipmentdetermines the access AP by performing step 304, the access AP can bedetermined quickly; if the user equipment determines the access AP byperforming step 305 to step 309, an AP with higher signal quality and/orsignal strength can be determined.

310. The user equipment or the access AP sends identificationinformation of the access AP to the base station controller.

Optionally, the user equipment may send the identification informationof the access AP to the base station controller after determining theaccess AP, and the user equipment may also send the identificationinformation of the access AP to the base station controller afterdetermining the access AP and accessing the WLAN through the access AP.The access AP may send the identification information of the access APto the base station controller after the access of the user equipment.

311. After receiving the identification information of the access AP,the base station controller may determine a fourth AP set according tolocation information of the user equipment, where the fourth AP setincludes at least one AP.

Specifically, the base station controller may determine at least one APwhose coverage includes a location of the user equipment as an AP in thefourth AP set, and may also determine at least one AP whose coverage isadjacent to a search scope in which the user equipment is capable ofperforming AP search as an AP in the fourth AP set.

Optionally, all APs in the fourth AP set may belong o the first AP setor the third AP set, or the at least one AP in the fourth AP set may notbelong to the first AP set or the third AP set.

312. The base station controller notifies the user equipment of thefourth AP set. The user equipment may determine a switching target or acandidate target set by using the fourth AP set.

Optionally, in a case where all APs in the fourth AP set belong to thefirst AP set or the third AP set, the base station controller may sendonly indication information to the user equipment, and the userequipment may determine information about the fourth AP set from thereceived information about the first AP set and/or the receivedinformation about the third AP set according to the indicationinformation.

Optionally, in a case where the fourth AP set is the same as the firstAP set or the third AP set, the base station controller may notify theuser equipment that the fourth AP set is identical with the first AP setor the third AP set. The user equipment may determine a switching targetor a candidate target set by using the first AP set or the third AP set.

Optionally, the base station controller may further send the informationabout the fourth AP set to the user equipment.

Optionally, the information about the fourth AP set includes at leastone of the following: a channel number of at least one AP in the fourthAP set, identification information of at least one AP in the fourth APset, information about a beacon channel of at least one AP in the fourthAP set, a security parameter of at least one AP in the fourth AP set,transmit signal strength of at least one AP in the fourth AP set, andtransmit signal quality of at least one AP in the fourth AP set, wherethe information about the beacon channel of the at least one AP in thefourth AP set is a transmission time and period of the beacon channel ofthe at least one AP in the fourth AP set, the transmission time of thebeacon channel is a relative time relative to a reference time of themobile network, and the security parameter of the at least one AP in thefourth AP set includes a key used for access and/or an authenticationtype.

313. The user equipment receives a first threshold or a first thresholdand a second threshold sent by the base station controller. Optionally,step 313 may be performed with any one of the following steps: step 303,step 308, and step 312. Step 313 may also be an independent stepperformed before or after any one of step 302 to step 312.

Optionally, the first threshold and/or the second threshold may besignal quality or signal strength. Measurement information correspondsto the first threshold and/or the second threshold and may be signalquality or signal strength.

Optionally, step 321 is performed in a case where the user equipmentreceives only the first threshold. In a case where the user equipmentreceives the first threshold and the second threshold, any one of thefollowing combinations of steps may he performed: step 314 and step 320;step 315, step 316, and step 320; step 315, step 317, step 318, step319, and step 320; and step 314 and step 321.

314. After receiving the second threshold sent by the base stationcontroller, the user equipment determines a switching target in a casewhere measurement information of the access AP is lower than the secondthreshold, where the user equipment determines, according to the secondthreshold, that the switching target may be an AP or the base stationcontroller.

Specifically, after accessing the access AP, the user equipment needs todetect signal quality and/or signal strength of the access AP all thetime. If the measurement information (signal quality or signal strength)of the access AP is lower than the second threshold, the user equipmentmeasures measurement information of the at least one AP in the fourth APset.

In a case where at least one AP whose measurement information is notlower than the second threshold exists in the fourth AP set, the userequipment may determine an AP (for example, select an AP with thehighest signal quality or signal strength) as the switching target fromthe at least one AP whose measurement information is not lower than thesecond threshold.

Optionally, the user equipment may further perform an authenticationprocedure and/or an association procedure with the AP through the basestation controller, so that the AP confirms the identity of the userequipment.

Step 320 is performed in a case where the user equipment determines thatthe switching target is an AP.

In a case where no AP whose measurement information is not lower thanthe second threshold exists in the fourth AP set, the user equipmentdetermines that the switching target is the base station controller.Step 321 performed in a case where the user equipment determines thatthe switching target is the base station controller.

315. After receiving the second threshold sent by the base stationcontroller, the user equipment determines a candidate target set in acase where measurement information of the measured access AP is lowerthan the second threshold, where the candidate target set includes atleast one AP.

Specifically, after accessing the access AP, the user equipment needs todetect signal quality and/or signal strength of the access AP all thetime. If the measurement information (signal quality or signal strength)of the access AP is lower than the second threshold, the user equipmentmeasures measurement information of the at least one AP in the fourth APset. In a case where at least one AP whose measurement information isnot lower than the second threshold exists in the fourth AP set, theuser equipment may determine the candidate target set from the at leastone AP whose measurement information is not lower than the secondthreshold. For example, the user equipment may determine an AP whosemeasurement information is higher than a specified threshold as an AP inthe candidate target set, and the user equipment may also determine,according to a specified proportion, an AP whose measurement informationranks high as an AP in the candidate target set. It should be noted thatthe preceding method is only an example, a method for determining an APin the candidate target set is not limited to the preceding method.

316. The user equipment may determine a switching target from the atleak one AP in the candidate target set.

Optionally, the user equipment may further perform an authenticationand/or an association procedure with the at least one AP in thecandidate target set through the base station controller, so that the atleast one AP in the candidate target set confirms the identity of theuser equipment. Specifically, the user equipment may send authenticationinformation and/or association information to the at least one AP in thecandidate target set through the base station controller. The userequipment may select one AP (for example, select an AP with the highestsignal quality or signal strength) as the switching target from at leastone AP on which association and authentication have been completed inthe candidate target set.

317. The base station controller receives the candidate target setnotified by he user equipment.

Specifically, the user equipment may send indication information to thebase station controller, and the base station controller may determineinformation about the candidate target set from the determined fourth APset according to the indication information. The user equipment may alsosend the information about the candidate target set to the base stationcontroller.

Optionally,the information about the candidate target set includes thirdinformation and fourth information, where the third information includesat least one of the following: signal quality of at least one AP in thecandidate target set, signal strength of at least one AP in thecandidate target set, and a path loss of at least one AP in thecandidate target set; and the fourth information includes at least oneof the following: a channel number of at least one AP in the candidatetarget set, identification information of at least one AP in thecandidate target set, and information about a beacon channel of at leastone AP in the candidate target set, where the information about thebeacon channel of the at least one AP in the candidate target set is atransmission time and period of the beacon channel of the at least oneAP in the candidate target set, and the transmission time of the beaconchannel is a relate e time relative to a reference time of the mobilenetwork.

318. The base station controller may determine a switching target fromthe at least one AP in the candidate target set.

Optionally, the base station controller may determine the switchingtarget according to the information about the candidate target setand/or other information (for example, load and a congestion degree of abackhaul) about the at least one AP in the candidate target set. Forexample, the base station controller may select an AP with the highestsignal quality or signal strength as the switching target.

Optionally, the user equipment may further perform an authenticationand/or an association procedure with the at least one AP in thecandidate target set through the base station controller, so that the atleast one AP in the candidate target set confirms the identity of theuser equipment. Specifically, the user equipment may send authenticationinformation and/or association information to the at least one AP in thecandidate target set through the base station controller. The basestation controller may select one AP (for example, select an AP with thehighest signal quality or signal strength) as the switching target fromat least one AP on which association and authentication have beencompleted in the candidate target set.

319. The base station controller notifies the user equipment of theswitching target.

Specifically, the base station controller may send indicationinformation to the user equipment, and the user equipment may determineinformation about the switching target from the determined candidatetarget set according to the indication information. The base stationcontroller may also send the information about the switching target tothe user equipment.

Optionally, the information about the switching target includes at leastone of the following: a channel number of the switching target,identification information of the switching target, information about abeacon channel of the switching target, and a security parameter of theswitching target, where the information about the beacon channel of theswitching target is a transmission time and period of the beacon channelof the switching target, the transmission time of the beacon channel isa relative time relative to a reference time of the mobile network, andthe security parameter of the switching target includes a key used foraccess and/or an authentication type.

320. In a case where the user equipment determines that the measurementinformation of the access AP is lower than the first threshold and theuser equipment determines that the switching target is an AP, the userequipment disconnects from the access AP, accesses the switching target,and performs data connection through the switching target to access theInternet. Further, the user equipment may further send theidentification information of the switching target to the radio networkcontroller. The case in which the user equipment determines that theswitching target is an AP includes the following: The user equipment maydirectly determine that the switching target is an AP, the userequipment may determine the switching target from the candidate targetset, or the user equipment may also receive the switching targetdetermined by the base station controller.

321. In a case where the user equipment determines that the measurementinformation of the access AP is lower than the first threshold and theuser equipment needs to access the base station controller, the userequipment disconnects from the access AP, accesses the base stationcontroller, and performs data connection through the base stationcontroller to access the Internet. The case in which the user equipmentneeds to access the base station controller includes the following: Theuser equipment receives only the first threshold, or the user equipmentdetermines that the switching target is the base station controlleraccording to the second threshold.

Specifically, after accessing the access AP, the user equipment needs todetect signal quality and/or signal strength of the access AP all thetime. If the measurement information (signal quality or signal strength)of the access AP is lower than the first threshold, the user equipmentmay send a connection establishment request or a data transmission statemessage to the base station controller. Specifically, in a case where noconnection to the base station controller exists, the user equipmentsends a connection establishment request to the base station controller,so as to reestablish a connection with the base station controller; in acase where a connection to the base station controller is not released,the user equipment sends a data transmission state message to the basestation controller, so as to restore data transmission with the basestation controller, where the data transmission state message includes amessage such as a measurement report and a cell update request. Further,the connection establishment request or the data transmission statemessage may further include indication information used to indicate thatthe WLAN is unavailable. After the user equipment sends the connectionestablishment request or the data transmission state message to the basestation controller, the user equipment may disconnect from the accessAP, access the base station controller, and perform data connection withthe base station controller to access the Internet.

Optionally, if the user equipment does not receive a first switchingthreshold configuration, or signal quality or signal strength of theaccess AP is not lower than the first switching threshold but the signalquality or the signal strength of the access AP is not sufficient tosupport data transmission of the user equipment, the user equipment mayalso directly send a connection establishment request or a datatransmission state message to the base station controller. Specifically,in a case where no connection to the base station controller exists, theuser equipment sends a connection establishment request to the basestation controller, so as to reestablish a connection with the basestation controller; in a case where a connection to the base stationcontroller is not released, the user equipment sends a data transmissionstate message to the base station controller, so as to restore datatransmission with the base station controller, where the datatransmission state message includes a message such as a measurementreport and a cell update request. Further, the connection establishmentrequest or the data transmission state message may further includeindication information used to indicate that the WLAN is unavailable.After the user equipment sends the connection establishment request orthe data state restoration indication to the base station controller,the user equipment may disconnect from the access AP, access the basestation controller, and perform data connection with the base stationcontroller to access the Internet.

Optionally, identification information of an AP, an access AP, or aswitching target in the set is a unique identifier corresponding to theAP, for example, a BSSID, an SSID, an ESSID, or a MAC address.

According to the preceding method, when a user equipment needs to accessa WLAN through an AP to access the the Internet, a base stationcontroller may notify the user equipment of an available AP. In thisway, the user equipment can access the WLAN directly through theavailable AP and does not need to request a password from an operatorand enter the password during access.

According to the preceding method, the base station controller maynotify the user equipment of an AP to which the user equipment can beswitched, so as to assist the user equipment in accessing the AP towhich the user equipment can be switched or the base station controllerin the case of relatively poor signal quality or signal strength of anaccess AP. The user equipment can directly access the AP to which theuser equipment can be switched or the base station controller, and doesnot need to request, from an operator, a password of the AP to which theuser equipment can be switched and enter the password during the access.In this way, a switching procedure is smoother.

FIG. 4 is a schematic block diagram of a base station controlleraccording to an embodiment of the present application. The base stationcontroller 400 is a base station controller of a serving base station ofa user equipment and can perform the steps performed by the base stationcontroller in the preceding methods. The base station controller 400includes a receiving unit 401, a control unit 402, and a sending unit403.

The receiving unit 401 is configured to receive an access capabilityindication or access request sent by the user equipment.

The control unit 402 is configured to determine a first AP set in a casewhere the receiving unit 401 receives the access capability indicationor access request sent by the user equipment.

The sending unit 403 is configured to send information about the firstAP set to the user equipment according to the first AP set determined bythe control unit 402, so that the user equipment determines, accordingto the information about the first AP set, an access AP for accessing aWLAN.

Optionally, the information about the first AP set includes at least oneof the following: a channel number of at least one AP in the first APset, identification information of at least one AP in the first AP set,information about a beacon channel of at least one AP in the first APset, a security parameter of at least one AP in the first AP set,transmit signal strength of at least one AP in the first AP set, andtransmit signal quality of at least one AP in the first AP set, wherethe information about the beacon channel of the at least one AP in thefirst AP set is a sending time point and period of the beacon channel ofthe at least one AP in the first AP set, and the security parameter ofthe at least one AP in the first AP set includes a key used for accessand/or an authentication type.

Optionally, identification information of an AP or access AP in the setis a unique identifier corresponding to the AP, for example, a BSSID, anSSID, an ESSID, or a MAC address.

According to the base station controller 400, when a user equipmentneeds to access a WLAN through an AP to access the Internet, the basestation controller may notify the user equipment of an available AP. Inthis way, the user equipment can access the WLAN directly through theavailable AP and does not need to request a password from an operatorand enter the password during access.

FIG. 5 is a schematic block diagram of another base station controlleraccording to an embodiment of the present application. The base stationcontroller 500 is a base station controller of a serving base station ofa user equipment and can perform the steps performed by the base stationcontroller in the preceding methods. The base station controller 500 isan embodiment of the base station controller 400. The base stationcontroller 500 includes a receiving unit 501, a control unit 502, and asending unit 503.

The receiving unit 501 is configured to receive an access capabilityindication or access request sent by the user equipment, where theaccess capability indication is used to indicate that the user equipmentis capable of accessing a WLAN through an AP.

Optionally, the access capability indication and the access request maybe carried in a radio resource control (Radio Resource Control, RRC)connection establishment request message or an RRC connectionestablishment complete message. The RRC connection establishment requestmessage is the first message sent by the user equipment to a mobilenetwork, and the RRC connection establishment complete message is thefirst dedicated message sent by the user equipment to the mobilenetwork. Using the RRC connection establishment request message or theRRC connection establishment complete message to bear the accesscapability indication and the access request helps the base stationcontroller quickly perform WLAN access control according to the accessrequest.

The control unit 502 is configured to determine a first AP set in a casewhere the receiving unit 501 receives the access capability indicationor the access request, where the first AP set includes at least one AP.

The sending unit 503 is configured to send information about the firstAP set to the user equipment according to the first AP set determined bythe control unit.

Optionally, the information about the first AP set includes at least oneof the following: a channel number of at least one AP in the first APset, identification information of at least one AP in the first AP set,information about a beacon channel of at least one AP in the first APset, a security parameter of at least one AP in the first AP set,transmit signal strength of at least one Ap in the first AP set, andtransmit signal quality of at least one AP in the first AP set, wherethe information about the beacon channel of the at least one AP in thefirst AP set is a sending time point and period of the beacon channel ofthe at least one AP in the first AP set, and the security parameter ofthe at least one AP in the first AP set includes a key used for accessand/or an authentication type. Optionally, the information about thefirst AP set may be carried in an RRC connection establishment message,an RRC connection release message or a measurement control message. In acase where the information about the first AP set is carried in the RRCconnection release message, the base station controller releases an RRCconnection to the user equipment.

The receiving unit 501 is further configured to receive informationabout a second AP set sent by the user equipment.

Optionally, the information about the second AP set includes: firstinformation and second information, where the first information includesat least one of the following: signal quality of at least one AP in thesecond AP set, signal strength of at least one AP in the second AP set,and a path loss of at least one AP in the second AP set, and the secondinformation includes at least one of the following: a channel number ofat least one AP in the second AP set, identification information of atleast one AP in the second AP set, and information about a beaconchannel of at least one AP in the second AP set, where the informationabout the beacon channel of the at least one AP in the second AP set isa sending time point and period of the beacon channel of the at leastone AP in the second AP set.

The control unit 502 is further configured to determine a third AP setfrom the second AP set, where the third AP set includes at least one AP.

Optionally,the control unit 502 may determine the third AP set from theat least one AP in the second AP set according to a preset condition.For example, the control unit 502 may determine an AP whose signalquality or signal strength is higher than a specified threshold as an APin the third AP set, the control unit 502 may also determine, accordingto a specified proportion, an AP whose signal quality or signal strengthranks high as an AP in the third AP set, and the control unit 502 mayalso determine an AP in the third AP set according to other information(for example, load and a congestion degree of a backhaul) about the atleast one AP in the second AP set. It should be noted that the precedingmethod is only an example, a method for determining an AP in the thirdAP set is not limited to the preceding method.

The sending unit 503 is further configured to send information about theAP set determined by the control unit 502 to the user equipment.

Optionally, the information about the third. AP set includes at leastone of the following: a channel number of at least one AP in the thirdAP set, identification information of at least one AP in the third APset, information about a beacon channel of at least one AP in the thirdAP set, a security parameter of at least one AP in the third AP set,transmit signal strength of at least one AP in the third AP set, andtransmit signal quality of at least one AP in the third AP set, wherethe information about the beacon channel of the at least one AP in thethird AP set is a sending time point and period of the beacon channel ofthe at least one AP in the third AP set, and the security parameter ofthe at least one AP in the third AP set includes a key used for accessand/or an authentication type.

The receiving unit 501 is further configured to receive identificationinformation of the access AP sent by the user equipment or the accessAP.

Optionally, the access AP may he determined by the user equipment fromthe first AP set, and the access AP may also be determined by the userequipment from the third AP set. If the user equipment determines theaccess AP from the first AP set, the access AP can be determinedquickly; if the user equipment determines the access AP from the thirdAP set, an AP with higher signal quality and/or signal strength can hedetermined.

The control unit 502 is further configured to determine a fourth AP setaccording to location information of the user equipment after thereceiving unit 501 receives the identification information of the accessAP, where the fourth AP set includes at least one AP.

Specifically, the control unit 502 may determine at least one AP whosecoverage includes a location in which the user equipment is located asan AP in the fourth AP set, and may also determine at least one AP whosecoverage is adjacent to a search scope in which the user equipment iscapable of performing AP search as an AP in the fourth AP set.

Optionally, all APs in the fourth AP set may belong to the first AP setor the third AP set, or the at least one AP in the fourth AP set may notbelong to the first AP set or the third AP set.

The sending unit 503 is further configured to notify the user equipmentof the fourth AP set. The user equipment may determine a switchingtarget or a candidate target set by using the fourth AP set.

Optionally, in a case where all APs in the fourth AP set belong to thefirst AP set or the third AP set, the sending unit 503 may send onlyindication information to the user equipment, and the user equipment maydetermine information about the fourth AP set from the receivedinformation about the first AP set and/or the received information aboutthe third AP set according to the indication information.

Optionally, in a case where the fourth AP set is the same as the firstAP set or the third AP set, the sending unit 503 may notify the userequipment that the fourth. AP set is identical with the first AP set orthe third AP set. The user equipment may determine a switching target ora candidate target set by using the first AP set or the third AP set.

Optionally, the base station controller may further send the informationabout the fourth AP set to the user equipment.

Optionally, the information about the fourth AP set includes at leastone of the following: a channel number of at least one AP in the fourthAP set, identification information of at least one AP in the fourth APset, information about a beacon channel of at least one AP in the fourthAP set, a security parameter of at least one AP in the fourth AP set,transmit signal strength of at least one AP in the fourth AP set, andtransmit signal quality of at least one AP in the fourth AP set, wherethe information about the beacon channel of the at least one AP in thefourth AP set is a transmission time and period of the beacon channel ofthe at least one AP in the fourth AP set, the transmission time of thebeacon channel is a relative time relative to a reference time of themobile network, and the security parameter of the at least one AP in thefourth AP set includes a key used for access and/or an authenticationtype.

The sending unit 503 is further configured to send a first threshold ora first threshold and a second threshold to the user equipment.

Optionally, the sending unit 503 may send the first threshold or thefirst threshold and the second threshold together with the informationabout the first AP set or the information about the third AP set, orbefore or after sending the information about the first AP set or theinformation about the third AP set. The sending unit 503 may also sendthe first threshold or the first threshold and the second threshold atthe time of notifying the fourth AP set, and may also send the firstthreshold or the first threshold and the second threshold before orafter notifying the fourth AP set.

Optionally, the first threshold and/or the second threshold may besignal quality or signal strength. The measurement informationcorresponds to the first threshold and/or the second threshold and maybe signal quality or signal strength.

The receiving unit 501 is further configured to receive the candidatetarget set notified by the user equipment.

Specifically, the receiving unit 501 may receive indication informationsent by the user equipment, and the control unit 502 may determineinformation about the candidate target set from the determined fourth APset according to the indication information. The receiving unit 501 mayfurther receive the information about the candidate target set sent bythe user equipment.

Optionally, the information about the candidate target set includesthird information and fourth information, where the third informationincludes at least one of the following: signal quality of at least oneAP in the candidate target set, signal strength of at least one AP inthe candidate target set, and a path loss of at least one AP in thecandidate target set; and the fourth information includes at least oneof the following: a channel number of at least one AP in the candidatetarget set, identification information of at least one AP in thecandidate target set, and information about a beacon channel of at leastone AP in the candidate target set, where the information about thebeacon channel of the at least one AP in the candidate target set is atransmission time and period of the beacon channel of the at least oneAP in the candidate target set, and the transmission time of the beaconchannel is a relative time relative to a reference time of the mobilenetwork.

The control unit 502 is further configured to determine a switchingtarget from the at least one AP in the candidate target set.

Optionally, the control unit 502 may determine the switching targetaccording to the information about the candidate target set and/or otherinformation (for example, load and a congestion degree of a backhaul)about the at least one AP in the candidate target set. For example, thecontrol unit 502 may select an AP with the highest signal quality orsignal strength as the switching target.

The receiving unit 501 is further configured to receive authenticationinformation and/or association information sent by the user equipment,and the sending unit 503 is further configured to forward theauthentication information and/or the association information to the atleast one AP in the candidate target set. The control unit 502 isfurther configured to select one AP (for example, select an AP with thehighest signal quality or signal strength) as the switching target froman AP on which association and/or authentication has been completed.

The sending unit 503 is further configured to notify the switchingtarget determined by the control unit 502 to the user equipment.

Specifically, the sending unit 503 may send indication information tothe user equipment, and the user equipment may determine informationabout the switching target from the determined candidate target setaccording to the indication information. The sending unit 503 may alsosend the information about the switching target to the user equipment.

Optionally, the information about the switching target includes at leastone of the following: a channel number of the switching target,identification information of the switching target, information about abeacon channel of the switching target, and a security parameter of theswitching target, where the information about the beacon channel of theswitching target is a transmission time and period of the beacon channelof the switching target, the transmission time of the beacon channel isa relative time relative to a reference time of the mobile network, andthe security parameter of the switching target includes a key used foraccess and/or an authentication type.

The receiving unit 501 is further configured to: in a case where theswitching target is an AP and the AP is determined by the userequipment, receive identification information of the switching targetsent by the user equipment and/or the switching target.

The receiving unit 501 is further configured to receive a connectionestablishment request or a data transmission state message sent by theuser equipment.

The control unit 502 is further configured to reestablish a connectionwith the user equipment in a case where the receiving unit 501 receivesthe connection establishment request. Alternatively, the control unit502 is further configured to restore a connection with the userequipment in a case where the receiving unit 501 receives the datatransmission state message.

Optionally, the data transmission state message includes a message suchas a measurement report and a cell update request. Further, theconnection establishment request or the data transmission state messagemay further include indication information used to indicate that theWLAN is unavailable.

Optionally, identification information of an AP, an access AP, or aswitching target in the set is a unique identifier corresponding to theAP, for example, a BSSID, an SSID, an ESSID, or a MAC address.

According to the base station controller 500, when a user equipmentneeds to access a WLAN through an AP to access the Internet, the basestation controller may notify the user equipment of an available AP. Itthis way, the user equipment can access the WLAN directly through theavailable AP and does not need to request a password from an operatorand enter the password during access.

According to the base station controller 500, the base stationcontroller may notify the user equipment of an AP to which the userequipment can be switched, so as to assist the user equipment inaccessing the AP to which the user equipment can be switched or the basestation controller in the case of relatively poor signal quality orsignal strength of an access AP. The user equipment can directly accessthe AP to which the user equipment can be switched or the base stationcontroller, and does not need to request, from an operator, a passwordof the AP to which the user equipment can be switched and enter thepassword during the access. In this way, a switching procedure issmoother.

FIG. 6 is a schematic block diagram of a user equipment according to anembodiment of the present application. The user equipment 600 canperform the steps performed by the user equipment in the precedingmethods. The user equipment 600 includes a sending unit 601, a receivingunit 602, and a control unit 603.

The sending unit 601 is configured to send an access capabilityindication or access request of the user equipment to a base stationcontroller of a serving base station of the user equipment, so that thebase station controller determines a first AP set in the case ofreceiving the access capability indication or the access request, wherethe first AP set includes at least one AP, and the access capabilityindication sent by the user equipment is used to indicate that the userequipment is capable of accessing a WLAN through an AP.

The receiving unit 602 is configured to receive information about thefirst AP set sent by the base station controller.

The control unit 603 is configured to determine, according to theinformation about the first AP set, an access AP for accessing the WLAN.

Optionally, the information about the first AP set includes at least oneof the following: a channel number of at least one AP in the first APset, identification information of at least one AP in the first AP set,information about a beacon channel of at least one AP in the first APset, a security parameter of at least one AP in the first AP set,transmit signal strength of at least one AP in the first AP set, andtransmit signal quality of at least one AP in the first AP set, wherethe information about the beacon channel of the at least one AP in thefirst AP set is a sending tune point and period of the beacon channel ofthe at least one AP in the first AP set, and the security parameter ofthe at least one AP in the first AP set includes a key used for accessand/or an authentication type.

Optionally, identification information of an AP or access AP in the setis a unique identifier corresponding to the AP, for example, a BSSID, anSSID, an ESSID, or a MAC address.

According to the user equipment 600, when the user equipment needs toaccess a WLAN through an AP to access the Internet, a base stationcontroller may notify the user equipment of an available AP. In thisway, the user equipment can access the WLAN directly through theavailable AP and does not need to request a password from an operatorand enter the password during access.

FIG. 7 is a schematic block diagram of another user equipment accordingto an embodiment of the present application. The user equipment 700 canperform the steps performed by the user equipment in the precedingmethods. The user equipment 700 is an embodiment of the user equipment600. The user equipment 700 includes a sending unit 701, a receivingunit 702, and a control unit 703.

The sending unit 701 is configured to send an access capabilityindication or an access request to a base station controller of aserving base station of the user equipment 700, where the accesscapability indication is used to indicate that the user equipment 700 iscapable of accessing a WLAN through an AP.

Optionally, the access capability indication and the access request maybe carried in a radio resource control (RRC) connection establishmentrequest message or an RRC connection establishment complete message. TheRRC connection establishment request message is the first message sentby the user equipment to a mobile network, and the RRC connectionestablishment complete message is the first dedicated message sent bythe user equipment to the mobile network. Using the RRC connectionestablishment request message or the RRC connection establishmentcomplete message to bear the access capability indication and the accessrequest helps the base station controller quickly perform WLAN accesscontrol according to the access request.

The receiving unit 702 is configured to receive information about afirst AP set that is determined by the base station controller in a casewhere the base station controller receives the access capabilityindication or the access request, where the first AP set includes atleast one AP.

Optionally, the information about the first AP set includes at least oneof the following: a channel number of at least one AP in the first APset, identification information of at least one AP in the first AP set,information about a beacon channel of at least one AP in the first APset, a security parameter of at least one AP in the first AP set,transmit signal strength of at least one AP in the first AP set, andtransmit signal quality of at least one AP in the first AP set, wherethe information about the beacon channel of the at least one AP in thefirst AP set is a sending time point and period of the beacon channel ofthe at least one AP in the first AP set, and the security parameter ofthe at least one AP in the first AP set includes a key used for accessand/or an authentication type.

Optionally, the information about the first AP set may be carried in anRRC connection establishment message, an RRC connection release messageor a measurement control message. In a case where the information aboutthe first AP set is carried in the RRC connection release message, thebase station controller releases an RRC connection to the userequipment.

The control unit 703 is configured to determine an access AP foraccessing the WLAN from the at least one AP in the received first APset.

Optionally, in a case where the first AP set includes only one AP, thecontrol unit 703 determines that the access AP is the AP. The controlunit 703 may further determine at least one of the following accordingto the information about the first AP set: signal strength of at leastone AP in the first AP set, signal quality of at least one AP in thefirst AP set, and a path loss of at least one AP in the first AP set.The control unit 703 may select an AP with the highest signal quality orsignal strength in the first AP set as the access AP, and may alsoselect an AP with the lowest path loss in the first AP set as the accessAP.

The control unit 703 may further be configured to determine a second APset from the at least one AP in the received first AP set, where thesecond AP set includes at least one AP.

Optionally, the control unit 703 may further determine at least one ofthe following according to the information about the first AP set:signal strength of at least one AP in the first AP set, signal qualityof at least one AP in the first AP set, and a path loss of at least oneAP in the first AP set. The control unit 703 may determine an AP in thesecond AP set from the at least one AP in the first AP set according toa preset condition. For example, the control unit 703 may determine anAP whose signal quality or signal strength is higher than a specifiedthreshold as an AP in the second AP set, and the control unit 703 mayalso determine, according to a specified proportion, an AP whose signalquality or signal strength ranks high as an AP in the second AP set. Itshould be noted that the preceding method is only an example, a methodfor determining an AP in the second AP set is not limited to thepreceding method.

The sending unit 701 may further be configured to send information aboutthe second AP set to the base station controller according to the secondAP set.

Optionally, the information about the second AP set includes: firstinformation and second information, where the first information includesat least one of the following: signal quality of the at least one AP inthe second AP set, signal strength of the at least one AP in the secondAP set, and a path loss of the at least one AP in the second AP set, andthe second information includes at least one of the following: a channelnumber of at least one AP in the second AP set, identificationinformation of at least one AP in the second AP set, and informationabout a beacon channel of at least one AP in the second AP set, wherethe information about the beacon channel of the at least one AP in thesecond AP set is a sending time point and period of the beacon channelof the at least one AP in the second AP set.

The receiving unit 702 may further be configured to receive informationabout a third AP set that is determined by the base station controllerfrom the second AP set.

Optionally, the information about the third AP set includes at least oneof the following: a channel number of at least one AP in the third APset, identification information of at least one AP in the third AP set,information about a beacon channel of at least one AP in the third APset, a security parameter of at least one AP in the third AP set,transmit signal strength of at least one AP in the third AP set, andtransmit signal quality of at least one AP in the third AP set, wherethe information about the beacon channel of the at least one AP in thethird AP set is a sending time point and period of the beacon channel ofthe at least one AP in the third. AP set, and the security parameter ofthe at least one AP in the third AP set includes a key used for accessand/or an authentication type.

The control unit 703 may further he configured to determine an access APfor accessing the WLAN from the at least one AP in the third AP set.

Optionally, in a case where only one AP exists in the third AP set, theaccess AP is the AP. In a case where more than one AP exists in thethird AP set, the control unit 703 may select an AP with the highestsignal quality or signal strength in the third AP set as the access AP,and may also select an AP with the lowest path loss in the third AP setas the access AP. The signal strength, signal quality, or path loss ofan AP in the third AP set may be determined by the control unit 703according to the information about the third AP set.

It should be noted that the user equipment may determine the access APdirectly from the first AP set, or the user equipment may also determinethe access AP by using the second AP set and the third AP set. If theuser equipment determines the access AP directly from the first AP set,the access AP can be determined quickly; if the user equipmentdetermines the access AP by using the second AP set and the third APset, an AP with higher signal quality and/or signal strength can bedetermined.

The sending unit 701 is further configured to send identificationinformation of the access AP to the base station controller.

The receiving unit 702 is further configured to receive a fourth AP setnotified by the base station controller.

Optionally, in a case where all APs in the fourth AP set belong to thefirst AP set or the third AP set, the receiving unit 702 may receiveindication information sent by the base station controller to the userequipment 700, and the control unit 703 may determine information aboutthe fourth AP set from the received information about the first AP setand/or the received information about the third AP set according to theindication information.

Optionally, in a case where the fourth AP set is the same as the firstAP set or the third AP set, the receiving unit 702 may receive anotification of the base station controller, where the notification isused to indicate that the fourth AP set is identical with the first APset or the third AP set. The user equipment 700 may determine aswitching target or a candidate target set by using the first AP set orthe third AP set.

Optionally,the receiving unit 702 may receive the information about thefourth AP set.

Optionally, the information about the fourth AP set includes at leastone of the following: a channel number of at least one AP in the fourthAP set, identification information of at least one AP in the fourth APset, information about a beacon channel of at least one AP in the fourthAP set, a security parameter of at least one AP in the fourth AP set,transmit signal strength of at least one AP in the fourth AP set, andtransmit signal quality of at least one AP in the fourth AP set, wherethe information about the beacon channel of the at least one AP in thefourth AP set is a transmission time and period of the beacon channel ofthe at least one AP in the fourth AP set, the transmission time of thebeacon channel is a relative time relative to a reference time of themobile network, and the security parameter of the at least one AP in thefourth AP set includes a key used for access and/or an authenticationtype.

The receiving unit 702 is further configured to receive a firstthreshold or a first threshold and a second threshold sent by the basestation controller.

The control unit 703 is further configured to determine a switchingtarget after the receiving unit 702 receives the second threshold and ina case where measurement information of the measured access AP is lowerthan the second threshold. The control unit 703 determines, according tothe second threshold, that the switching target may be an AP or the basestation controller.

Specifically, after the user equipment accesses the access AP, thecontrol unit 703 needs to detect signal quality and/or signal strengthof the access AP all the time. If the measurement information (signalquality or signal strength) of the access AP is lower than the secondthreshold, the control unit 703 measures measurement information of theat least one AP in the fourth AP set.

in a case where at least one AP whose measurement information is notlower than the second threshold exists in the fourth AP set, the controlunit 703 may determine an AP (for example, select an AP with the highestsignal quality or signal strength) as the switching target from the atleast one AP whose measurement information is not lower than the secondthreshold.

Optionally, the user equipment 700 may further perform an authenticationprocedure and/or an association procedure with the AP through the basestation controller, so that the AP confirms the identity of the userequipment.

In a case where no AP whose measurement information is not lower thanthe second threshold exists in the fourth AP set, the control unit 703determines that the switching target is the base station controller.

The control unit 703 is further configured to determine a candidatetarget set after the receiving unit 702 receives the second thresholdand in a case where measurement information of the measured access AP islower than the second threshold.

Specifically, after the user equipment accesses the access AP, thecontrol unit 703 needs to detect signal quality and/or signal strengthof the access AP all the time. If the measurement information (signalquality or signal strength) of the access AP is lower than the secondthreshold, the control unit 703 measures measurement information of theat least one AP in the fourth AP set. In a case where at least one APwhose measurement information is not lower than the second thresholdexists in the fourth AP set, the control unit 703 may determine thecandidate target set from the at least one AP whose measurementinformation is not lower than the second threshold. For example, thecontrol unit 703 may determine an AP whose measurement information ishigher than a specified threshold as an AP in the candidate target set,and the control unit 703 may also determine, according to a specifiedproportion, an AP whose measurement information ranks high as an AP inthe candidate target set. It should be noted that the preceding methodis only an example, a method for determining an AP in the candidatetarget set is not limited to the preceding method.

The control unit 703 may further be configured to determine a switchingtarget from the at least one AP in the candidate target set.

Optionally, the user equipment 700 may further perform an authenticationand/or an association procedure with the at least one AP in thecandidate target set through the base station controller, so that the atleast one AP in the candidate target set confirms the identity of theuser equipment. The sending unit 701 may further be configured to sendauthentication information and/or association information to the atleast one AP in the candidate target set through the base stationcontroller. The control unit 703 may select one AP (for example, selectan AP with the highest signal quality or signal strength) as theswitching target from at least one AP on which association andauthentication have been completed in the candidate target set.

The sending unit 701 may further be configured to notify the basestation controller of the candidate target set.

Optionally, the sending unit 701 may send indication information to thebase station controller, and the base station controller may determineinformation about the candidate target set from the determined fourth APset according to the indication information. The sending unit 701 mayalso send the information about the candidate target set to the basestation controller.

Optionally, the information about the candidate target set includesthird information and fourth information, where the third informationincludes at least one of the following: signal quality of the at leastone AP in the candidate target set, signal strength of the at least oneAP in the candidate target set, and a path loss of the at least one APin the candidate target set; and the fourth information includes atleast one of the following: a channel number of at least one AP in thecandidate target set, identification information of at least one AP inthe candidate target set, and information about a beacon channel of atleast one AP in the candidate target set, where the information aboutthe beacon channel of the at least one AP in the candidate target set isa transmission time and period of the beacon channel of the at least oneAP in the candidate target set, and the transmission time of the beaconchannel is a relative time relative to a reference time of the mobilenetwork.

Optionally, the user equipment 700 may further perform an authenticationand/or an association procedure with the at least one AP in thecandidate target set through the base station controller, so that the atleast one AP in the candidate target set confirms the identity of theuser equipment. Specifically, the sending unit 701 may sendauthentication information and/or association information to the atleast one AP in the candidate target set through the base stationcontroller. The base station controller may select one AP (for example,select an AP with the highest signal quality or signal strength) as theswitching target from at least one AP on which association andauthentication have been completed in the candidate target set.

The receiving unit 702 may further be configured to receive theswitching target notified by base station controller.

Specifically, the receiving unit 702 may receive indication informationsent by the base station controller to the user equipment, and thecontrol unit 703 may determine information about the switching targetfrom the determined candidate target set according to the indicationinformation. The receiving unit 702 may receive the information aboutthe switching target sent by the base station controller to the userequipment.

Optionally, the information about the candidate target set includes atleast one of the following: a channel number of the switching target,identification information of the switching target, information about abeacon channel of the switching target, and a security parameter of theswitching target, where the information about the beacon channel of theswitching target is a transmission time and period of the beacon channelof the switching target, the transmission time of the beacon channel isa relative time relative to a reference time of the mobile network, andthe security parameter of the switching target includes a key used foraccess and/or an authentication type.

The control unit 703 may further be configured to: in a case where thecontrol unit 703 determines that the measurement information of theaccess AP is lower than the first threshold and the control unit 703determines that the switching target is an AP, disconnect from theaccess AP, access the switching target, and perform data connectionthrough the switching target to access the Internet. Further, thesending unit 701 may further be configured to send the identificationinformation of the switching target to the radio network controller. Thecase in which the control unit 703 determines that the switching targetis an AP includes the following: The control unit 703 may directlydetermine that the switching target is an AP, the control unit 703 maydetermine the switching target from the candidate target set, or thereceiving unit 702 may also receive the switching target determined bythe base station controller.

The control unit 703 may further be configured to: in a case where thecontrol unit 703 determines that the measurement information of theaccess AP is lower than the first threshold and the user equipment needsto access the base station controller, disconnect from the access AP,access the base station controller, and perform data connection throughthe base station controller to access the Internet. The case in whichthe user equipment needs to access the base station controller includesthe following: The receiving unit 702 receives only the first threshold,or the control unit 703 determines that the switching target is the basestation controller according to the second threshold.

Specifically, after the user equipment 700 accesses the access AP, thecontrol unit 703 needs to detect signal quality and/or signal strengthof the access AP all the time. If the measurement information (signalquality or signal strength) of the access AP is lower than the firstthreshold, the sending unit 701 may further be configured to send aconnection establishment request or a data transmission state message tothe base station controller. Specifically, in a case where no connectionexists between the user equipment and the base station controller, thesending unit 701 sends a connection establishment request to the basestation controller, so that the user equipment reestablishes aconnection with the base station controller; in a case where aconnection to the base station controller is not released, the sendingunit 701 sends a data transmission state message to the base stationcontroller, so that the user equipment restores data transmission withthe base station controller, where the data transmission state messageincludes a message such as a measurement report and a cell updaterequest. Further, the connection establishment request or the datatransmission state message of the base station may further includeindication information used to indicate that the WLAN is unavailable.After the sending unit 701 sends the connection establishment request orthe data state restoration indication to the base station controller,the control unit 703 may disconnect from the access AP, access the basestation controller,and perform data connection with the base stationcontroller to access the Internet.

Optionally, if the receiving unit 702 does not receive a first switchingthreshold configuration, or the control unit 703 determines that signalquality or signal strength of the access AP is not lower than the firstswitching threshold but the signal quality or the signal strength of theaccess AP is not sufficient to support data transmission of the userequipment 700, the sending unit 701 may also directly send a connectionestablishment request or a data transmission state message to the basestation controller. Specifically, in a case where no connection existsbetween the user equipment and the base station controller, the sendingunit 701 sends a connection establishment request to the base stationcontroller, so that the user equipment reestablishes a connection withthe base station controller, in a case where a connection to the basestation controller is not released, the sending unit 701 sends a datatransmission state message to the base station controller, so that theuser equipment restores data transmission with the base stationcontroller, where the data transmission state message includes a messagesuch as a measurement report and a cell update request. Further, theconnection establishment request or the data transmission state messageof the base station may further include indication information used toindicate that the WLAN is unavailable. After the sending unit 701 sendsthe connection establishment request or the data state restorationindication to the base station controller, the control unit 703 maydisconnect from the access AP, access the base station controller, andperform data connection with the base station controller to access theInternet.

Optionally, identification information of an AP, an access AP, or aswitching target in the set is a unique identifier corresponding to theAP, for example, a BSSID, an SSD, an ESSID, or a MAC address.

According to the user equipment 700, when the user equipment needs toaccess a WLAN through an AP to access the Internet, a base stationcontroller may notify the user equipment of an available AP. In thisway, the user equipment can access the WLAN directly through theavailable AP and does not need to request a password from an operatorand enter the password during access.

According to the user equipment 700, the base station controller maynotify the user equipment of an AP to which the user equipment can beswitched, so as to assist the user equipment in accessing the AP towhich the user equipment can be switched or the base station controllerin the case of relatively poor signal quality or signal strength of anaccess AP. The user equipment can directly access the AP to which theuser equipment can be switched or the base station controller, and doesnot need to request, from an operator, a password of the AP to which theuser equipment can be switched and enter the password during the access.In this way, a switching procedure is smoother.

Another embodiment of the present application provides a base stationcontroller. The base station controller is a base station controller ofa serving base station of a user equipment and can perform the stepsperformed by the base station controller in the preceding methods. Thebase station controller includes a receiver, a processor, and atransmitter.

The receiver is configured to receive an access capability indication oraccess request sent by the user equipment, where the access capabilityindication is used to indicate that the user equipment is capable ofaccessing a WLAN through an AP.

Optionally, the access capability indication and the access request maybe carried in a radio resource control (RRC) connection establishmentrequest message or an RRC connection establishment complete message. TheRRC connection establishment request message is the first message sentby the user equipment to a mobile network, and the RRC connectionestablishment complete message is the first dedicated message sent bythe user equipment to the mobile network. Using the RRC connectionestablishment request message or the RRC connection establishmentcomplete message to bear the access capability indication and the accessrequest helps the base station controller quickly perform WLAN accesscontrol according to the access request.

The processor is configured to determine a first AP set in a case wherethe receiver receives the access capability indication or the accessrequest, where the first AP set includes at least one AP.

The transmitter is configured to send information about the first AP setto the user equipment according to the first AP set determined by acontrol unit.

Optionally, the information about the first AP set includes at least oneof the following: a channel number of at least one AP in the first APset, identification information of at least one AP in the first AP set,information about a beacon channel of at least one AP in the first APset, a security parameter of at least one AP in the first AP set,transmit signal strength of at least one AP in the first AP set, andtransmit signal quality of at least one AP in the first AP set, wherethe information about the beacon channel of the at least one AP in thefirst AP set is a sending time point and period of the beacon channel ofthe at least one AP in the first AP set, and the security parameter ofthe at least one AP in the first AP set includes a key used for accessand/or an authentication type. Optionally, the information about thefirst AP set may be carried in an RRC connection establishment message,an RRC connection release message or a measurement control message. In acase where the information about the first AP set is carried in the RRCconnection release message, the base station controller releases an RRCconnection to the user equipment.

The receiver is further configured to receive information about a secondAP set sent by the user equipment.

Optionally, the information about the second AP set includes: firstinformation and second information, where the first information includesat least one of the following: signal quality of at least one AP in thesecond AP set, signal strength of at least one AP in the second AP set,and a path loss of at least one AP in the second AP set, and the secondinformation includes at least one of the following: a channel number ofat least one AP in the second AP set, identification information of atleast one AP in the second AP set, and information about a beaconchannel of at least one AP in the second AP set, where the informationabout the beacon channel of the at least one AP in the second AP set isa sending time point and period of the beacon channel of the at leastone AP in the second AP set.

The processor is further configured to determine a third AP set from thesecond AP set, where the third AP set includes at least one AP.

Optionally, the processor may determine the third AP set from the atleast one AP in the second AP set according to a preset condition. Forexample, the processor may determine an AP whose signal quality orsignal strength is higher than a specified threshold as an AP in thethird AP set, the processor may also determine, according to a specifiedproportion, an AP whose signal quality or signal strength ranks high asan AP in the third AP set, and the processor may also determine an AP inthe third AP set according to other information (for example, load and acongestion degree of a backhaul) about the at least one AP in the secondAP set. It should be noted that the preceding method is only an example,a method for determining an AP in the third AP set is not limited to thepreceding method.

The transmitter is further configured to send information about thethird AP set determined by the processor to the user equipment.

Optionally, the information about the third AP set includes at least oneof the following: a channel number of at least one AP in the third APset, identification information of the at least one AP in the third APset, information about a beacon channel of at least one AP in the thirdAP set, a security parameter of at least one AP in the third AP set,transmit signal strength of at least one AP in the third AP set, andtransmit signal quality of at least one AP in the third AP set, wherethe information about the beacon channel of the at least one AP in thethird AP set is a sending time point and period of the beacon channel ofthe at least one AP in the third AP set, and the security parameter ofthe at least one AP in the third AP set includes a key used fur accessand/or an authentication type.

The receiver is further configured to receive identification informationof the access AP sent by the user equipment or the access AP.

Optionally, the access AP may be determined by the user equipment fromthe first AP set, and the access AP may also be determined by the userequipment from the third AP set. If the user equipment determines theaccess AP from the first AP set, the access AP can be determinedquickly; if the user equipment determines the access AP from the thirdAP set, an AP with higher signal quality and/or signal strength can bedetermined.

The processor is further configured to determine a fourth AP setaccording to location information of the user equipment after thereceiver receives the identification information of the access AP, wherethe fourth AP set includes at least one AP.

Specifically, the processor may determine at least one AP whose coverageincludes a location in which the user equipment is located as an AP inthe fourth AP set, and may also determine at least one AP whose coverageis adjacent to a search scope in which the user equipment is capable ofperforming AP search as an AP in the fourth AP set.

Optionally, all APs in the fourth AP set may belong to the first AP setor the third. AP set, or the at least one AP in the fourth AP set maynot belong to the first AP set or the third AP set.

The transmitter is further configured to notify the user equipment ofthe fourth AP set. The user equipment may determine a switching targetor a candidate target set by using the fourth AP set.

Optionally, in a case where all APs in the fourth AP set belong to thefirst AP set or the third AP set, the transmitter may send onlyindication information to the user equipment, and the user equipment maydetermine information about the fourth AP set from the receivedinformation about the first AP set and/or the received information aboutthe third AP set according to the indication information.

Optionally, in a case where the fourth AP set is the same as the firstAP set or the third AP set, the transmitter may notify the userequipment that the fourth AP set is identical with the first AP set orthe third AP set. The user equipment may determine a switching target ora candidate target set by using the first AP set or the third AP set.

Optionally, the base station controller may further send the informationabout the fourth AP set to the user equipment.

Optionally, the information about the fourth AP set includes at leastone of the following: a channel number of at least one AP in the fourthAP set, identification information of at least one AP in the fourth APset, information about a beacon channel of at least one AP in the fourthAP set, a security parameter of at least one AP in the fourth AP set,transmit signal strength of at least one AP in the fourth AP set, andtransmit signal quality of at least one AP in the fourth AP set, wherethe information about the beacon channel of the at least one AP in thefourth AP set is a transmission time and period of the beacon channel ofthe at least one AP in the fourth AP set, the transmission time of thebeacon channel is a relative time relative to a reference time of themobile network, and the security parameter of the at least one AP in thefourth AP set includes a key used for access and/or an authenticationtype.

The transmitter is further configured to send a first threshold or afirst threshold and a second threshold to the user equipment.

Optionally, the transmitter may send the first threshold or the firstthreshold and the second threshold together with the information aboutthe first AP set or the information about the third AP set, or before orafter sending the information about the first AP set or the informationabout the third AP set. The transmitter may also send the firstthreshold or the first threshold and the second threshold at the time ofnotifying the fourth AP set, and may also send the first threshold orthe first threshold and the second threshold before or after notifyingthe fourth AP set.

Optionally, the first threshold and/or the second threshold may besignal quality or signal strength. The measurement informationcorresponds to the first threshold and/or the second threshold and maybe signal quality or signal strength.

The receiver is further configured to receive the candidate target setnotified by the user equipment.

Specifically, the receiver may receive indication information sent bythe user equipment, and the processor may determine information aboutthe candidate target set from the determined fourth AP set according tothe indication information. The receiver may further receive theinformation about the candidate target set sent by the user equipment.

Optionally, the information about the candidate target set includesthird information and fourth information, where the third informationincludes at least one of the following: signal quality of at least oneAP in the candidate target set, signal strength of at least one AP inthe candidate target set, and a path loss of at least one AP in thecandidate target set; and the fourth information includes at least oneof the following: a channel number of at least one AP in the candidatetarget set, identification information of at least or AP in thecandidate target set, and information about a beacon channel of at leastone AP in the candidate target set, where the information about thebeacon channel of the at least one AP in the candidate target set is atransmission time and period of the beacon channel of the at least oneAP in the candidate target set, and the transmission time of the beaconchannel is a relative time relative to a reference time of the mobilenetwork.

The processor is further configured to determine a switching target fromthe at least one AP in the candidate target set.

Optionally, the processor may determine the switching target accordingto the information about the candidate target set and/or otherinformation (for example, load and a congestion degree of a backhaul)about the at least one AP in the candidate target set. For example, theprocessor may select an AP with the highest signal quality or signalstrength as the switching target.

The receiver is further configured to receive authentication informationand/or association information sent by the user equipment, and thetransmitter is further configured to forward the authenticationinformation and/or the association information to the at least one AP inthe candidate target set. The processor is further configured to selectone AP (for example, select an AP with the highest signal quality orsignal strength) as the switching target from an AP on which associationand/or authentication has been completed.

The transmitter is further configured to notify the switching targetdetermined by the processor to the user equipment.

Specifically, the transmitter may send indication information to theuser equipment, and the user equipment may determine information aboutthe switching target from the determined candidate target set accordingto the indication information. The transmitter may also send theinformation about the switching target to the user equipment.

Optionally, the information about the switching target includes at leastone of the following: a channel number of the switching target,identification information of the switching target, information about abeacon channel of the switching target, and a security parameter of theswitching target, where the information about the beacon channel of theswitching target is a transmission time and period of the beacon channelof the switching target, the transmission time of the beacon channel isa relative time relative to a reference time of the mobile network, andthe security parameter of the switching target includes a key used foraccess and/or an authentication type.

The receiver is further configured to: in a case where the switchingtarget is an AP and the AP is determined by the user equipment, receiveidentification information of the switching target sent by the userequipment and/or the switching target.

The receiver is further configured to receive a connection establishmentrequest or a data transmission state message sent by the user equipment.

The processor is further configured to reestablish a connection with theuser equipment in a case where the receiver receives the connectionestablishment request. Alternatively, the processor is furtherconfigured to restore a connection with the user equipment in a casewhere the receiver receives the data transmission state message.

Optionally, the data transmission state message includes a message suchas a measurement report and a cell update request. Further, theconnection establishment request or the data transmission state messagemay further include indication information used to indicate that theWLAN is unavailable.

Optionally, identification information of an AP, an access AP, or aswitching target in the set is a unique identifier corresponding to theAP, for example, a BSSID, an SSM, an ESSID, or a MAC address.

According to the base station controller, when a user equipment needs toaccess a WLAN through an AP to access the Internet, the base stationcontroller may notify the user equipment of an available AP. In thisway, the user equipment can access the WLAN directly through theavailable AP and does not need to request a password from an operatorand enter the password during access.

According to the base station controller, the base station controllermay notify the user equipment of an AP to which the user equipment canbe switched, so as to assist the user equipment in accessing the AP towhich the user equipment can be switched or the base station controllerin the case of relatively poor signal quality or signal strength of anaccess AP. The user equipment can directly access the AP to which theuser equipment can be switched or the base station controller, and doesnot need to request, from an operator, a password of the AP to which theuser equipment can be switched and enter the password during the access.In this way, a switching procedure is smoother.

Another embodiment of the present application provides a user equipment.The user equipment can perform the steps performed by the user equipmentin the preceding methods. The user equipment includes a transmitter, areceiver, and a processor.

The transmitter is configured to send an access capability indication oran access request to a base station controller of a serving base stationof the user equipment 700, where the access capability indication isused to indicate that the user equipment is capable of accessing a WLANthrough an AP.

Optionally, the access capability indication and the access request maybe carried in a radio resource control (RRC) connection establishmentrequest message or an RRC connection establishment complete message. TheRRC connection establishment request message is the first message sentby the user equipment to a mobile network, and the RRC connectionestablishment complete message is the first dedicated message sent bythe user equipment to the mobile network. Using the RRC connectionestablishment request message or the RRC connection establishmentcomplete message to bear the access capability indication and the accessrequest helps the base station controller quickly perform WLAN accesscontrol according to the access request.

The receiver is configured to receive information about a first AP setthat is determined by the base station controller in a case where thebase station controller receives the access capability indication or theaccess request, where the first AP set includes at least one AP.

Optionally, the information about the first AP set includes at least oneof the following: a channel number of at least one AP in the first APset, identification information of at least one AP in the first AP set,information about a beacon channel of at least one AP in the first APset, a security parameter of at least one AP in the first AP set,transmit signal quality of at least one AP in the first AP set, andtransmit signal strength of at least one AP in the first AP set, wherethe information about the beacon channel of the at least one AP in thefirst AP set is a sending time point and period of the beacon channel ofthe at least one AP in the first AP set, and the security parameter ofthe at least one AP in the first AP set includes a key used for accessand/or an authentication type.

Optionally, the information about the first AP set may be carried in anRRC connection establishment message, an RRC connection release messageor a measurement control message. In a case where the information aboutthe first AP set is carried in the RRC connection release message, thebase station controller releases an RRC connection to the userequipment.

The processor is configured to determine an access AP for accessing theWLAN from the at least one AP in the received first AP set.

Optionally, in a case where the first AP set includes only one AP, theprocessor determines that the access AP is the AP. The processor mayfurther determine at least one of the following according to theinformation about the first AP set: signal strength of at least one APin the first AP set, signal quality of at least one AP in the first APset, and a path loss of at least one AP in the first AP set. Theprocessor may select an AP with the highest signal quality or signalstrength in the first AP set as the access AP, and may also select an APwith the lowest path loss in the first AP set as the access AP.

The processor may further be configured to determine a second AP setfrom the at least one AP in the received first AP set, where the secondAP set includes at least one AP.

Optionally, the processor may further determine at least one of thefollowing according to the information about the first AP set: signalstrength of the at least one AP in the first AP set, signal quality ofthe at least one AP in the first AP set, and a path loss of the at leastone AP in the first AP set. The processor may determine an AP in thesecond AP set from the at least one AP in the first AP set according toa preset condition. For example, the processor may determine an AP whosesignal quality or signal strength is higher than a specified thresholdas an AP in the second AP set, and the processor may also determine,according to a specified proportion, an AP whose signal quality orsignal strength ranks high as an AP in the second AP set. It should benoted that the preceding method is only an example, a method fordetermining an AP in the second AP set is not limited to the precedingmethod.

The transmitter may further be configured to send information about thesecond AP set to the base station controller according to the second APset.

Optionally, the information about the second AP set includes: firstinformation and second information, where the first information includesat least one of the following: signal quality of at least one AP in thesecond AP set, signal strength of at least one AP in the second AP set,and a path loss of at least one AP in the second AP set, and the secondinformation includes at least one of the following: a channel number ofat least one AP in the second AP set, identification information of atleast one AP in the second AP set, and information about a beaconchannel of at least one AP in the second AP set, where the informationabout the beacon channel of the at least one AP in the second AP set isa sending time point and period of the beacon channel of the at leastone AP in the second AP set.

The receiver may further be configured to receive information about athird AP set that is determined by the base station controller from thesecond AP set.

Optionally, the information about the third AP set includes at least oneof the following: a channel number of at least one AP in the third APset, identification information of at least one AP in the third AP set,information about a beacon channel of at least one AP in the third APset, a security parameter of at least one AP in the third AP set,transmit signal strength of at least one AP in the third AP set, andtransmit signal quality of at least one AP in the third AP set, wherethe information about the beacon channel of the at least one AP in thethird AP set is a sending time point and period of the beacon channel ofthe at least one AP in the third AP set, and the security parameter ofthe at least one AP in the third AP set includes a key used for accessand/or an authentication type.

The processor may further be configured to determine an access AP foraccessing the WLAN from the at least one AP in the third AP set.

Optionally, in a case where only one AP exists in the third AP set, theaccess AP is the AP. In a case where more than one AP exists in thethird AP set, the processor may select an AP with the highest signalquality or signal strength in the third AP set as the access AP, and mayalso select an AP with the lowest path loss in the third AP set as theaccess AP. The signal strength, signal quality, or path loss of an AP inthe third AP set may be determined by the processor according to theinformation about the third AP set.

It should be noted that the user equipment may determine the access APdirectly from the first AP set, or the user equipment may also determinethe access AP by using the second AP set and the third AP set. If theuser equipment determines the access AP directly from the first AP set,the access AP can be determined quickly; if the user equipmentdetermines the access AP by using the second AP set and the third APset, an AP with higher signal quality and/or signal strength can bedetermined.

The transmitter is further configured to send identification informationof the access AP to the base station controller.

The receiver is further configured to receive a fourth AP set notifiedby the base station controller.

Optionally, in a case where all APs in the fourth AP set belong to thefirst AP set or the third AP set, the receiver may receive indicationinformation sent by the base station controller to the user equipment,and the processor may determine information about the fourth AP set fromthe received information about the first AP set and/or the receivedinformation about the third AP set according to the indicationinformation.

Optionally, in a case where the fourth AP set is the same as the firstAP set or the third AP set, the receiver may receive a notification ofthe base station controller, where the notification is used to indicatethat the fourth AP set is identical with the first AP set or the thirdAP set. The user equipment may determine a switching target or acandidate target set by using the first AP set or the third AP set.

Optionally, the receiver may receive the information about the fourth APset.

Optionally, the information about the fourth AP set includes at leastone of the following: a channel number of at least one AP in the fourthAP set, identification information of at least one AP in the fourth APset, information about a beacon channel of at least one AP in the fourthAP set, a security parameter of at least one AP in the fourth AP set,transmit signal strength of at least one AP in the fourth AP set, andtransmit signal quality of at least one AP in the fourth AP set, wherethe information about the beacon channel of the at least one AP in thefourth AP set is a transmission time and period of the beacon channel ofthe at least one AP in the fourth AP set, the transmission time of thebeacon channel is a relative time relative to a reference time of themobile network, and the security parameter of the at least one AP in thefourth AP set includes a key used for access and/or an authenticationtype.

The receiver is further configured to receive a first threshold or afirst threshold and a second threshold sent by the base stationcontroller.

The processor is further configured to determine a switching targetafter the receiver receives the second threshold and in a case wheremeasurement information of the measured access AP is lower than thesecond threshold. The processor determines, according to the secondthreshold, that the switching target may be an AP or the base stationcontroller.

Specifically, after the user equipment accesses the access AP, theprocessor needs to detect signal quality and/or signal strength of theaccess AP all time. If the measurement information (signal quality orsignal strength) of the access AP is lower than the second threshold,the processor measures measurement information of the at least one AP inthe fourth AP set

In a case where at least one AP whose measurement information is notlower than the second threshold exists in the fourth AP set, theprocessor may determine an AP (for example, select an AP with thehighest signal quality or signal strength) as the switching target fromthe at least one AP whose measurement information is not lower than thesecond threshold.

Optionally, the user equipment may further perform an authenticationprocedure and/or an association procedure with the AP through the basestation controller, so that the AP confirms the identity of the userequipment.

In a case where no AP whose measurement information is not lower thanthe second threshold exists in the fourth AP set, the processordetermines that the switching target is the base station controller.

The processor is further configured to determine a candidate target setafter the receiver receives the second threshold and in a case wheremeasurement information of the measured access AP is lower than thesecond threshold.

Specifically, after the user equipment accesses the access AP, theprocessor needs to detect signal quality and/or signal strength of theaccess AP all the time. If the measurement information (signal qualityor signal strength) of the access AP is lower than the second threshold,the processor measures measurement information of the at least one AP inthe fourth AP set. In a case where at least one AP whose measurementinformation is not lower than the second threshold exists in the fourthAP set, the processor may determine the candidate target set from the atleast one AP whose measurement information is not lower than the secondthreshold. For example, the processor may determine an AP whosemeasurement information is higher than a specified threshold as an AP inthe candidate target set, and the processor may also determine,according to a specified proportion, an AP whose measurement informationranks high as an AP in the candidate target set. It should be noted thatthe preceding method is only an example, a method for determining an APin the candidate target set is not limited to the preceding method.

The processor is further configured to determine a switching target fromthe at least one AP in the candidate target set.

Optionally, the user equipment may further perform an authenticationand/or an association procedure with the at least one AP in thecandidate target set through the base station controller, so that the atleast one AP in the candidate target set confirms the identity of theuser equipment. The transmitter may further be configured to sendauthentication information and/or association information to the atleast one AP in the candidate target set through the base stationcontroller. The processor may select one AP (for example, select an APwith the highest signal quality or signal strength) as the switchingtarget from at least one AP on which association and authentication havebeen completed in the candidate target set.

The transmitter may further be configured to notify the base stationcontroller of the candidate target set.

Optionally, the transmitter may send indication information to the basestation controller, and the base station controller may determineinformation about the candidate target set from the determined fourth APset according to the indication information. The transmitter may alsosend the information about the candidate target set to the base stationcontroller.

Optionally, the information about the candidate target set includesthird information and fourth information, where the third informationincludes at least one of the following: signal quality of at least oneAP in the candidate target set, signal strength of at least one AP inthe candidate target set, and a path loss of at least one AP in thecandidate target set; and the fourth information includes at least oneof the following: a channel number of at least one AP in the candidatetarget set, identification information of at least one AP in thecandidate target set, and information about a beacon channel of at leastone AP in the candidate target set, where the information about thebeacon channel of the at least one AP in the candidate target set is atransmission time and period of the beacon channel of the at least oneAP in the candidate target set, and the transmission time of the beaconchannel is a relative time relative to a reference time of the mobilenetwork.

Optionally, the user equipment may further perform an authenticationand/or an association procedure with the at least one AP in thecandidate target set through the base station controller, so that the atleast one AP in the candidate target set confirms the identity of theuser equipment. Specifically, the transmitter ay send authenticationinformation and/or association information to the at least one AP in thecandidate target set through the base station controller. The basestation controller may select one AP (for example, select an AP with thehighest signal quality or signal strength) as the switching target fromat least one AP on which association and authentication have beencompleted in the candidate target set.

The receiver may further be configured to receive a switching targetnotified by the base station controller.

Specifically, the receiver may receive indication information sent bythe base station controller to the user equipment, and the processor maydetermine information about the switching target from the determinedcandidate target set according to the indication information. Thereceiver may receive the information about the switching target sent bythe base station controller to the user equipment.

Optionally, the information about the candidate target set includes atleast one of the following: a channel number f the switching target,identification information of the switching target, information about abeacon channel of the switching target, and a security parameter of theswitching target, where the information about the beacon channel of theswitching target is a transmission time and period of the beacon channelof the switching target, the transmission time of the beacon channel isa relative time relative to a reference time of the mobile network, andthe security parameter of the switching target includes a key used foraccess and/or an authentication type.

The processor may further be configured to: in a case where theprocessor determines that the measurement information of the access APis lower than the first threshold and the processor determines that theswitching target is an AP, disconnect from the access AP, access theswitching target, and perform data connection through the switchingtarget to access the Internet. Further, the transmitter may further beconfigured to send the identification information of the switchingtarget to the radio network controller. The case in which the processordetermines that the switching target is an AP includes the following:The processor may directly determine that the switching target is an AP,the processor may determine the switching target from the candidatetarget set, or the processor may also receive the switching targetdetermined by the base station controller.

The processor may further be configured to: in a case where theprocessor determines that the measurement information of the access APis lower than the first threshold and the user equipment needs to accessthe base station controller, disconnect from the access AP, access thebase station controller,and perform data connection through the basestation controller to access the Internet. The case in which the userequipment needs to access the base station controller includes thefollowing: The receiver receives only the first threshold, or theprocessor determines that the switching target is the base stationcontroller according to the second threshold.

Specifically, after the user equipment accesses the access AP, theprocessor needs to detect signal quality and/or signal strength of theaccess AP all the time. If the measurement information (signal qualityor signal strength) of the access AP is lower than the first threshold,the transmitter may further be configured to send a connectionestablishment request or a data transmission state message to the basestation controller. Specifically, in a case where no connection existsbetween the user equipment and the base station controller, thetransmitter sends a connection establishment request to the base stationcontroller, so that the user equipment reestablishes a connection withthe base station controller; in a case where a connection to the basestation controller is not released, the transmitter sends a datatransmission state message to the base station controller, so that theuser equipment restores data transmission with the base stationcontroller, where the data transmission state message includes a messagesuch as a measurement report and a cell update request. Further, theconnection establishment request or the data transmission state messageof the base station may further include indication information used toindicate that the WLAN is unavailable. After the transmitter sends theconnection establishment request or the data state restorationindication to the base station controller, the processor may disconnectfrom the access AP, access the base station controller, and perform dataconnection with the base station controller to access the Internet.

Optionally, if the receiver does not receive a first switching thresholdconfiguration, or the processor determines that signal quality or signalstrength of the access AP is not lower than the first switchingthreshold but the signal quality or the signal strength of the access APis not sufficient to support data transmission of the user equipment,the transmitter may also directly send a connection establishmentrequest or a data transmission state message to the base stationcontroller. Specifically, in a case where no connection exists betweenthe user equipment and the base station controller, the transmittersends a connection establishment request to the base station controller,so that the user equipment reestablishes a connection with the basestation controller; in a case where a connection to the base stationcontroller is not released, the transmitter sends a data transmissionstate message to the base station controller, so that the user equipmentrestores data transmission with the base station controller, where thedata transmission state message includes a message such as a measurementreport and a cell update request. Further, the connection establishmentrequest or the data transmission state message of the base station mayfurther include indication information used to indicate that the WLAN isunavailable. After the transmitter sends the connection establishmentrequest or the data state restoration indication to the base stationcontroller, the processor may disconnect from the access AP, access thebase station controller, and perform data connection with the basestation controller to access the Internet,

Optionally, identification information of an AP, an access AP, or aswitching target in the set is a unique identifier corresponding to theAP, for example, a BSSID, an SSID, an ESSID, or a MAC address.

According to the user equipment, when the user equipment needs to accessa WLAN through an AP to access the Internet, a base station controllermay notify the user equipment of an available AP. In this way, the userequipment can access the WLAN directly through the available AP and doesnot need to request a password from an operator and enter the passwordduring access.

According to the user equipment, the base station controller may notifythe user equipment of an AP to which the user equipment can be switched,so as to assist the user equipment in accessing the AP to which the userequipment can be switched or the base station controller in the case ofrelatively poor signal quality or signal strength of an access AP. Theuser equipment can directly access the AP to which the user equipmentcan be switched or the base station controller, and does not need torequest, from an operator, a password of the AP to which the userequipment can be switched and enter the password during the access. Inthis way, a switching procedure is smoother.

A person of ordinary skill in the art may be aware that, in combinationwith the examples described in the embodiments disclosed in thisspecification, units and algorithm steps may be implemented byelectronic hardware, or a combination of computer software andelectronic hardware. Whether the functions are performed by hardware orsoftware depends on particular applications and design constraintconditions of the technical solutions. A person skilled in the art mayimplement the described functions for each particular application byusing different methods, but it should not be considered that theimplementation goes beyond the scope of the present application.

It may be clearly understood by a person skilled in the art that, forthe purpose of convenient and brief description, for a detailed workingprocess of the foregoing system, apparatus, and unit, reference may bemade to the corresponding process in the foregoing method embodiments,and the details are not described herein again.

In the several embodiments provided in the present application, itshould be understood that the disclosed system, apparatus, and methodmay be implemented in other manners. For example, the describedapparatus embodiments are merely exemplary. For example, the unitdivision is merely logical function division and may be other divisionin actual implementation. For example, a plurality of units orcomponents may be combined or integrated into another system, or somefeatures may be ignored or not performed. In addition, the displayed ordiscussed mutual couplings or direct couplings or communicationconnections may be implemented through some interfaces. The indirectcouplings or communication connections between the apparatuses or unitsmay be implemented in electronic, mechanical, or other forms.

The units described as separate parts may or may not be physicallyseparate, and parts displayed as units may or may not be physical units,may be located in one position, or may be distributed on a plurality ofnetwork units. A part or all of the units may be selected according toactual needs to achieve the objectives of the solutions of theembodiments.

In addition, functional units in the embodiments of the presentapplication may be integrated into one processing unit, or each of theunits may exist alone physically, or two or more units are integratedinto one unit.

When the functions are implemented in a form of a software functionalunit and sold or used as an independent product, the functions may bestored in a computer-readable storage medium. Based on such anunderstanding, the technical solutions of the present applicationessentially, or the part contributing to the prior art, or all or a partof the technical solutions may be implemented in a form of a softwareproduct. The computer software product is stored in a storage medium,and includes several instructions for instructing a computer device(which may be a personal computer, a server, or a network device) or aprocessor (processor) to perform all or a part of the steps of themethods described in the embodiments of the present application. Theforegoing storage medium includes: any medium that can store programcodes, such as a USB flash disk, a removable hard disk, a read-onlymemory (ROM), a random access memory (RAM), a magnetic disk, or anoptical disk.

The foregoing descriptions are merely specific implementation manners ofthe present application, but are not intended to limit the protectionscope of the present application. Any variation or replacement readilyfigured out by a person skilled in the art within the technical scopedisclosed in the present application shall fall within the protectionscope of the present application. Therefore, the protection scope of thepresent application is subject: to the appended claims.

What is claimed is:
 1. A method for use by a base station in a radioaccess network (RAN), the method comprising: receiving an accesscapability indication or an access request from a user equipment;determining a first access point (AP) set comprising at least one AP ofa wireless local area network (WLAN); and sending information about thefirst AP set and a first threshold to the user equipment.
 2. The methodaccording to claim 1, wherein the information about the first AP setcomprises identification information of at least one AP in the first APset.
 3. The method according to claim 2, wherein the identificationinformation of at least one AP in the first AP set comprises at leastone of: a basic service set identifier (BSSID), a service set identifier(SSID), an extended service set identifier (ESSID), or a media accesscontrol (MAC) address.
 4. The method according to claim 1, wherein: theaccess capability indication or the access request are carried in aradio resource control (RRC) connection establishment request message oran RRC connection establishment complete message; or the informationabout the first AP set is carried in an RRC connection establishmentmessage, an RRC connection release message or a measurement controlmessage.
 5. A base station in a radio access network (RAN), the basestation comprising: a processor, configured to: receive an accesscapability indication or an access request from a user equipment, anddetermine a first access point (AP) set comprising at least one AP of awireless local area network (WLAN); and a transmitter, configured tosend information about the first AP set and a first threshold to theuser equipment.
 6. The base station according to claim 5, wherein theinformation about the first AP set comprises identification informationof at least one AP in the first AP set.
 7. The base station according toclaim 6, wherein the identification information of at least one AP inthe first AP set comprises at least one of: a basic service setidentifier (BSSID), a service set identifier (SSID), an extended serviceset identifier (ESSID), or a media access control (MAC) address.
 8. Themethod according to claim 5, wherein: the access capability indicationor the access request are carried in a radio resource control (RRC)connection establishment request message or an RRC connectionestablishment complete message; or the information about the first APset is carried in an RRC connection establishment message, an RRCconnection release message or a measurement control message.
 9. Asystem, comprising: a base station in a radio access network (RAN), thebase station configured to: receive an access capability indication oraccess request, determine a first access point (AP) set comprising atleast one AP of a wireless local area network (WLAN), and sendinformation about the first AP set and a first threshold; and a userequipment, configured to: receive the first threshold and theinformation about the first AP set from the base station, access anaccess AP of the first AP set according to the information about thefirst AP set, and when measurement information of the access AP is lowerthan the first threshold, access the base station.
 10. The systemaccording to claim 9, wherein the information about the first AP setcomprises identification information of at least one AP in the first APset.
 11. The system according to claim 10, wherein the identificationinformation of at least one AP in the first AP set comprises at leastone of: a basic service set identifier (BSSID), a service set identifier(SSID), an extended service set identifier (ESSID), or a media accesscontrol (MAC) address.